Richardson v. Belleque ( 2017 )


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  • 236	                         December 14, 2017	                             No. 65
    IN THE SUPREME COURT OF THE
    STATE OF OREGON
    CHARLES EDWARD RICHARDSON,
    Respondent on Review,
    v.
    Brian BELLEQUE,
    Superintendent,
    Oregon State Penitentiary,
    Petitioner on Review.
    (CC 09C20407; CA A151817; SC S064185)
    On review from the Court of Appeals.*
    Argued and submitted January 12, 2017.
    Patrick M. Ebbett, Assistant Attorney General, Salem,
    argued the cause and filed the briefs for petitioner on review.
    Also on the briefs were Ellen F. Rosenblum, Attorney
    General, Benjamin Gutman, Solicitor General and Frederick
    M. Boss, Deputy Attorney General.
    Jason Weber, O’Connor Weber LLC, Portland, argued the
    cause and filed the brief for respondent on review.
    Dennis N. Balske and Jeffrey Erwin Ellis, Portland,
    filed the brief for amicus curiae Oregon Criminal Defense
    Lawyers Association.
    Before Balmer, Chief Justice, and Kistler, Walters,
    Landau, Nakamoto, and Flynn, Justices.**
    NAKAMOTO, J.
    The decision of the Court of Appeals and the judgment of
    the circuit court are affirmed.
    ______________
    **  On appeal from Marion County Circuit Court, Linda L. Bergman, Senior
    Judge 277 Or App 615, 373 P3d 1113 (2016).
    **  Baldwin, J., retired March 31, 2017, and did not participate in the decision
    of this case. Brewer, J., retired June 30, 2017, and did not participate in the deci-
    sion of this case. Duncan, J., did not participate in the consideration or decision of
    this case.
    Cite as 362 Or 236 (2017)	237
    Case Summary: Petitioner, who was convicted of first-degree manslaughter
    and second-degree assault and sentenced as a dangerous offender, sought post-
    conviction relief, alleging that counsel provided inadequate assistance at sen-
    tencing. At the sentencing proceeding, the prosecutor presented a psychiatrist
    who testified that petitioner suffered from an antisocial personality disorder, in
    part based on petitioner’s conduct as a juvenile. Petitioner’s defense counsel knew
    beforehand that the expert would testify adversely to petitioner, but he did not
    obtain significant records pertaining to petitioner when he was a juvenile, con-
    sult with a psychological expert, or secure testimony from an expert to rebut that
    evidence. In the post-conviction proceeding, petitioner presented evidence from a
    psychologist who reviewed records from one of petitioner’s juvenile incarcerations
    and interviewed petitioner, and who ultimately concluded that petitioner had not
    suffered from a conduct disorder when he was a youth, and therefore could not be
    diagnosed with an antisocial personality disorder as an adult. Held: Petitioner’s
    counsel had failed to conduct an adequate investigation and, in light of the nature
    and complexity of the dangerous-offender sentencing proceeding and the infor-
    mation that counsel knew, counsel’s decision not to consult an expert concerning
    the antisocial personality disorder diagnosis was not a reasonable exercise of
    professional skill and judgment. Had counsel adequately investigated petitioner’s
    past and consulted a psychological expert, he would have obtained petitioner’s
    juvenile mental health records and would have learned that the expert could pro-
    vide ammunition to oppose an enhanced dangerous-offender sentence, by rebut-
    ting the testimony of the psychiatrist and providing an explanation of petitioner’s
    conduct that was not as damaging as an antisocial personality disorder.
    The decision of the Court of Appeals and the judgment of the circuit court
    are affirmed.
    238	                                         Richardson v. Belleque
    NAKAMOTO, J.
    In this action for post-conviction relief, petitioner
    successfully contended that his defense counsel had ren-
    dered constitutionally inadequate representation during a
    presentence hearing concerning whether petitioner was a
    dangerous offender who suffered from a “severe personal-
    ity disorder” as provided in ORS 161.725(1)(a). Petitioner’s
    defense counsel cross-examined the psychiatrist who testi-
    fied for the state, but counsel had not investigated signifi-
    cant records regarding petitioner’s background or consulted
    with an expert before the hearing, nor did he introduce evi-
    dence from a defense expert at the hearing. The jury found
    that petitioner suffered from a severe personality disorder,
    and the trial court sentenced petitioner to a lengthy prison
    term as a dangerous offender.
    The post-conviction court concluded that defense
    counsel had provided inadequate assistance by failing
    (1) to reasonably investigate and to consult with an expert
    before deciding that cross-examination alone was appropri-
    ate and (2) to present testimony from a defense expert to
    rebut the psychiatrist’s testimony that petitioner had an
    antisocial personality disorder. After concluding that peti-
    tioner had been prejudiced as a result, it vacated petitioner’s
    dangerous-offender sentence and remanded the case for
    resentencing. The Court of Appeals affirmed based on one
    of the post-conviction court’s conclusions: that defense coun-
    sel had provided inadequate assistance through failure to
    investigate and consult an expert and that petitioner suf-
    fered prejudice as a result. Richardson v. Belleque, 277 Or
    App 615, 627-29, 373 P3d 1113 (2016).
    On review, the state1 argues that the Court of
    Appeals erred for two alternative reasons: (1) defense coun-
    sel made a reasonable tactical decision to rely on cross-
    examination without consulting an expert and (2) regard-
    less, petitioner did not establish the required prejudice,
    which the state describes as a showing that, but for the defi-
    cient representation, it was “reasonably probable” that the
    1
    We refer to defendant Belleque, the Superintendent of the Oregon State
    Penitentiary, as “the state” for ease of reference.
    Cite as 362 Or 236 (2017)	239
    outcome of the sentencing phase of trial “would have been
    different.”
    As did the Court of Appeals, we conclude that
    defense counsel rendered inadequate assistance by failing
    to adequately investigate and to consult an expert in prepa-
    ration for the dangerous-offender hearing. We also conclude
    that defense counsel’s deficiency had “a tendency to affect
    the result of the prosecution”—the possibility that it affected
    the result is more than merely theoretical. Accordingly, peti-
    tioner established prejudice and is entitled to post-conviction
    relief. We therefore affirm the judgment of the trial court
    and the decision of the Court of Appeals.
    I. FACTS
    For background, we begin by briefly describing the
    facts adduced during the guilt phase of petitioner’s criminal
    prosecution. As the Court of Appeals described the incident
    that led to the convictions, in 2006, petitioner and his wife
    quarreled in a tavern, and then “petitioner walked out the
    back door to work on his truck. Petitioner later returned,
    exchanged words with his wife, and then left, slamming the
    door on his way out. This drew the attention of the victim,
    an elderly man, who followed petitioner out the door.” 277 Or
    App at 618. Petitioner then “punched him, causing him to
    fall.” 
    Id. Thereafter, petitioner
    went back into the bar, told
    his wife to leave with him, and they walked out “the same
    door, walking by the victim as they departed. The victim
    suffered a massive head injury and died the next day.” 
    Id. Petitioner was
    charged with first-degree manslaugh-
    ter, a Class A felony, and second-degree assault. The state’s
    theory of the case was that the attack was unprovoked. The
    defense theory was that petitioner had not acted knowingly
    (the assault charge) or recklessly (the manslaughter charge)
    and, instead, had hit the victim in self-defense.
    The defense relied on evidence that petitioner had
    witnessed numerous acts of domestic violence by his par-
    ents when he was a child, and later by other inmates while
    in prison, to argue that, when petitioner hit the victim, he
    reasonably feared that the victim intended to use a weapon
    against him. More particularly, petitioner testified that he
    240	                                            Richardson v. Belleque
    was quite close with his mother, had witnessed his father hit
    his mother on nearly a daily basis, and that one time he had
    hit his father when his father was hitting his mother. He
    also testified that he had had to fight in self-defense while
    in prison. In addition, petitioner’s sisters provided testimony
    indicating that petitioner’s early home life had been cha-
    otic. One sister testified that there was considerable abuse
    between their parents, primarily instigated by their mother,
    and that she left home as a teenager due to verbal abuse
    by their mother. Another sister testified that their parents
    were constantly physically fighting, and described their
    mother as “the violent one.” She also testified that petitioner
    had been confined in the Skipworth juvenile facility multiple
    times because he “wouldn’t go to school.” She also indicated
    that he had been in juvenile facilities at St. Mary’s Home for
    Boys and at MacLaren School for Boys.2
    A.  The Dangerous-Offender Sentence
    A jury found petitioner guilty of both charges. The
    state then sought to have petitioner sentenced as a “dan-
    gerous offender” on the manslaughter charge under ORS
    161.725 to 161.737.3 The presentence hearing at which the
    jury would determine whether petitioner was a dangerous
    offender was critically important to petitioner.
    In part, ORS 161.725(1)(a) provides that a sentenc-
    ing court may impose an enhanced dangerous-offender sen-
    tence if a defendant is being sentenced for a Class A felony
    and suffers from “a severe personality disorder indicating a
    propensity toward crimes that seriously endanger the life
    or safety of another.” First-degree manslaughter generally
    requires imposition of a mandatory minimum prison sen-
    tence of 10 years and carries a maximum indeterminate
    prison sentence of 20 years. ORS 137.700(3)(a)(D); ORS
    161.605(1); ORS 163.118(3). However, if the state proves
    that the defendant is a dangerous offender, upon proof of
    certain other facts, the determinate prison term for the
    2
    The MacLaren School for Boys is now known as the MacLaren Youth
    Correctional Facility.
    3
    Our references throughout this opinion are to the versions of ORS 161.725
    to 161.737 that were in effect in 2006 at the time of the crimes, although those
    statutes for the most part remain the same at present.
    Cite as 362 Or 236 (2017)	241
    crime, a Class A felony, can be increased, and the associated
    maximum indeterminate prison term becomes 30 years.4
    The state prevailed at the dangerous-offender hear-
    ing. The resulting dangerous-offender sentence that peti-
    tioner received was considerably longer than the sentence
    he otherwise would have received. The sentencing court set
    the determinate portion of petitioner’s dangerous-offender
    sentence at 260 months in prison (four months short of 22
    years) and imposed an indeterminate prison term of 30
    years.
    After he was sentenced, petitioner’s direct appeal
    was unsuccessful. State v. Richardson, 226 Or App 85, 202
    P3d 290, rev den, 346 Or 213 (2009).
    B.  Petitioner’s Dangerous-Offender Hearing
    The issue under our consideration in petitioner’s
    action for post-conviction relief relates to the dangerous-
    offender hearing and defense counsel’s preparation for it. We
    therefore describe that hearing in detail.
    By statute, a mental health professional will be
    appointed to evaluate a criminal defendant in a dangerous-
    offender case and will be involved in the process leading to
    the determination of dangerous-offender status. Under ORS
    161.735(1), the trial court is required to order “an examina-
    tion by a psychiatrist or psychologist.” The psychiatrist or
    psychologist must submit to the court “a written report of
    findings and conclusions, including an evaluation of whether
    the defendant is suffering from a severe personality disor-
    der indicating a propensity toward criminal activity.” ORS
    4
    Under ORS 161.737(2), when a court imposes a dangerous-offender sen-
    tence, “the sentencing judge shall indicate on the record the reasons for depar-
    ture and shall impose, in addition to the indeterminate sentence imposed under
    ORS 161.725, a required incarceration term that the offender must serve before
    release to post-prison supervision.” Under ORS 161.725(1), if a person is sen-
    tenced as a dangerous offender under ORS 161.725 to 161.737 for a Class A felony,
    “the maximum term of an indeterminate sentence of imprisonment for a danger-
    ous offender is 30 years.” In this case, the jury made findings in support of depar-
    ture that petitioner had committed the offense while on felony probation, that he
    had engaged in persistent involvement in similar offenses, and that he was being
    sentenced for a felony that seriously endangered the life or safety of another, and
    the court based the determinate portion of the dangerous offender sentence on
    those findings.
    242	                                  Richardson v. Belleque
    161.735(3). A presentence dangerous-offender hearing is
    then held, and, unless the criminal defendant waives the
    right to a jury, a jury makes the determination whether
    the criminal defendant has a “severe personality disorder
    indicating a propensity toward crimes that seriously endan-
    ger the life or safety of another.” ORS 161.725(1)(a); ORS
    161.735(5), (6).
    Accordingly, the trial court ordered a psychiatrist,
    George Suckow, M.D., to evaluate petitioner before the
    dangerous-offender hearing. After examining petitioner,
    Suckow submitted a written report to the court and counsel
    for the parties. His report was adverse to petitioner.
    Suckow’s report recounted that petitioner had a his-
    tory of physical abuse by his mother, and that he had been
    placed in the St. Mary’s Home for Boys at the age of 12 after
    running away from home. The report further indicated that
    petitioner had a history of getting into fights during grade
    school, as well as at St. Mary’s. It indicated that petitioner
    had issues with truancy from school, and he subsequently
    was placed at MacLaren, an Oregon youth correctional facil-
    ity, and then later in a federal youth correctional institution
    in California. Suckow’s report also recounted that petitioner
    had an extensive criminal history, beginning when he was a
    juvenile and continuing into his adult life, and “a pervasive
    pattern of disregard for and violation of the rights of others”
    that was “present prior to and after the age of 15.” Suckow
    diagnosed petitioner with amphetamine abuse as well as an
    antisocial personality disorder. Suckow ultimately opined
    that petitioner “does have a severe personality disorder indi-
    cating a propensity toward crimes that seriously endanger
    the life and safety of others.”
    Suckow testified at the dangerous-offender hearing,
    and its primary focus was on Suckow’s evidence. Suckow
    testified that his examination of petitioner involved a foren-
    sic interview that lasted approximately an hour, a review of
    petitioner’s history and background including investigation
    reports of the current crime and petitioner’s criminal record,
    and an assessment of petitioner’s present mental status. He
    explained how diagnoses were made under the American
    Psychiatric Association’s Diagnostic and Statistical Manual
    Cite as 362 Or 236 (2017)	243
    of Mental Disorders (4th ed text rev 2000), hereafter referred
    to as DSM-IV-TR, and the various categories of disorders in
    that manual. He explained, referring to the DSM-IV-TR, that
    “[a] personality disorder is a pervasive pattern of behavior
    that starts in childhood and lasts for life. And it’s not a psy-
    chosis, it’s not a major mental illness; it’s a way of behaving
    that that person has.” He indicated that people with antiso-
    cial personality disorders are “normal except they seem to
    do things that are wrong and they have little regard for the
    rights of others.” He described them as being prone to get-
    ting into fights and getting into trouble in school, and often
    having substance abuse problems. He opined that they tend
    to be deceitful and lacking in long-range goals. He noted,
    however, that they often do well in confinement due to the
    structure provided.
    Suckow explained that, in reaching a diagnosis of
    petitioner, he looked at petitioner’s pattern of behavior over
    the years and compared that to what petitioner told him. He
    concluded that petitioner had been fairly open and honest
    with him and had acknowledged that he had had “a lot of
    trouble in school and with the law.” Suckow further testi-
    fied that petitioner had said that, when he had been sent
    to St. Mary’s at the age of 12, he “didn’t like the discipline
    there and got into fights just like he had in grade school.”
    He described petitioner’s later juvenile history as involv-
    ing incarceration at MacLaren, followed by several years in
    a federal youth institution based on theft of a motorcycle.
    Petitioner also was incarcerated in an adult correctional
    facility in California, and he served time in a Washington
    state penitentiary for assault. In Oregon, petitioner pleaded
    guilty to numerous offenses over a number of years, and he
    had an attempted-murder charge reduced to second-degree
    assault. Suckow testified that petitioner acknowledged
    that he started to use amphetamines in the 1990s. Suckow
    opined that petitioner had had “a conduct disorder before
    the age of 15” and diagnosed petitioner with an antisocial
    personality disorder.
    Through cross-examination of Suckow, defense
    counsel’s main focus was on whether there was sufficient
    evidence that petitioner suffered from a “severe personality
    244	                                                 Richardson v. Belleque
    disorder,” as required for a dangerous-offender sentence.
    In his cross-examination, defense counsel highlighted the
    requirements under the DSM-IV-TR for a diagnosis of anti-
    social personality disorder and introduced, without objec-
    tion, documents showing the criteria for diagnoses of antiso-
    cial personality disorder and conduct disorder found in the
    DSM-IV-TR. He noted that a criterion for diagnosis of an
    antisocial personality disorder was “evidence of a conduct
    disorder with onset before age 15 years.”5 Defense counsel
    then asked Suckow whether, if a person did not meet that
    criterion, the person could be diagnosed with an antisocial
    personality disorder. Suckow indicated general agreement
    with counsel’s suggestion that that criterion must be met.
    Suckow then suggested that the age criterion was “not an
    absolute,” because people do not simply change on the date
    they reach a specified age.
    Defense counsel questioned Suckow about how much
    (or how little) Suckow knew concerning petitioner before peti-
    tioner was 15 years old. Counsel zeroed in on the criteria for
    a “conduct disorder” as specified in the DMS IV-TR, which
    required that three criteria be satisfied in order to make a
    5
    For ease of reference, we include a list of the pertinent criteria for diagnosis
    of an antisocial personality disorder under the DSM-IV-TR:
    “A.  There is a pervasive pattern of disregard for and violation of the rights
    of others occurring since age 15 years, as indicated by three (or more) of the
    following:
    “(1)  failure to conform to social norms with respect to lawful behaviors
    as indicated by repeatedly performing acts that are grounds for arrest
    “(2)  deceitfulness, as indicated by repeated lying, use of aliases, or con-
    ning others for personal profit or pleasure
    “(3)  impulsivity or failure to plan ahead
    “(4) irritability and aggressiveness, as indicated by repeated physical
    fights or assaults
    “(5)  reckless disregard for safety of self or others
    “(6)  consistent irresponsibility, as indicated by repeated failure to sus-
    tain consistent work behavior or honor financial obligations
    “(7)  lack of remorse, as indicated by being indifferent to or rationalizing
    having hurt, mistreated, or stolen from another.
    “B.  The individual is at least age 18 years.
    “C.  There is evidence of conduct disorder with onset before age 15 years.
    “D.  The occurrence of antisocial behavior is not exclusively during the course
    of schizophrenia or a manic episode.”
    DSM-IV-TR at 706.
    Cite as 362 Or 236 (2017)	245
    diagnosis of the disorder.6 One of the criteria for a conduct
    disorder is the initiation of physical fights. Counsel asked
    Suckow how that criterion could be satisfied, given that
    Suckow’s report did not specify who had initiated the fights
    Suckow had mentioned in the report. Suckow responded:
    “Well, he told me he got into fights. Now, to me, that doesn’t
    mean he was picked on; means he started them.” Suckow
    acknowledged that his report included that petitioner had
    reported being bullied by other children later at MacLaren,
    6
    For ease of reference, we include a list of the pertinent criteria for diagnosis
    of a conduct disorder under the DSM-IV-TR:
    “A.  A repetitive and persistent pattern of behavior in which the basic rights
    of others or major age-appropriate societal norms or rules are violated, as
    manifested by the presence of three (or more) of the following criteria in the
    past 12 months, with at least one criterion present in the past 6 months:
    “Aggression to people and animals
    “(1)  often bullies, threatens, or intimidates others
    “(2)  often initiates physical fights
    “(3)  has used a weapon that can cause serious physical harm to others
    (e.g., a bat, brick, broken bottle, knife, gun)
    “(4)  has been physically cruel to people
    “(5)  has been physically cruel to animals
    “(6)  has stolen while confronting a victim (e.g., mugging, purse snatch-
    ing, extortion, armed robbery)
    “(7)  has forced someone into sexual activity
    “Destruction of property
    “(8)  has deliberately engaged in fire setting with the intention of causing
    serious damage
    “(9) has deliberately destroyed others’ property (other than by fire
    setting)
    “Deceitfulness or theft
    “(10)  has broken into someone else’s house, building, or car
    “(11)  often lies to obtain goods or favors or to avoid obligations (i.e., ‘cons’
    others)
    “(12)  has stolen items of nontrivial value without confronting a victim
    (e.g., shoplifting, but without breaking and entering; forgery)
    “Serious violations of rules
    “(13) often stays out at night despite parental prohibitions, beginning
    before age 13 years
    “(14)  has run away from home overnight at least twice while living in
    parental or parental surrogate home (or once without returning for a lengthy
    period)
    “(15)  is often truant from school, beginning before age 13 years.”
    DSM-IV-TR at 98-99 (boldface in original).
    246	                                 Richardson v. Belleque
    and also that the report did not specify that petitioner had
    initiated any of the fights in which he had been involved
    before that time. Counsel then pressed the point, asking if
    Suckow was merely “guessing,” but Suckow responded: “No.
    I’m drawing a conclusion based upon his lifestyle and what
    he told me.” Counsel then ran through a number of other
    criteria for a conduct disorder, which Suckow acknowledged
    had not been satisfied.
    Counsel then asked about the criterion, “run away
    from home overnight at least twice while living in paren-
    tal or parental-surrogate home” or “once without returning
    for a lengthy period.” Counsel noted that Suckow’s report
    mentioned only one incident of petitioner running away from
    home before age 12, but Suckow responded that “it sounded
    to me like he’d done it more than once.” Counsel then noted
    that Suckow’s report suggested that petitioner had skipped
    school after leaving St. Mary’s at the age of 13 or 14, and
    he asked how that could satisfy the conduct disorder crite-
    rion of “often truant from school, beginning before age 13.”
    (Emphasis added.) Suckow’s response was that he believed
    the age cut-off to be an arbitrary figure and that he consid-
    ered that criterion satisfied.
    On redirect examination, the prosecutor shored
    up Suckow’s testimony. The prosecutor referred back to the
    diagnosis of antisocial personality disorder and asked, “is it
    correct that it does not require a diagnosis of conduct disor-
    der; it just requires some evidence thereof?” Suckow replied:
    “Yes.”
    In addition to Suckow’s testimony, the jury received
    information on petitioner’s criminal history, which included
    numerous property crimes and assaults dating back to the
    1970s. (Much of petitioner’s criminal history had already
    been revealed during the guilt phase of the trial, when
    petitioner testified in his own defense.) The prosecutor also
    presented evidence about a physical altercation between
    petitioner and several uniformed deputies that occurred
    during a recess at trial. Evidence was also presented from
    victims of some of petitioner’s prior crimes, including evi-
    dence of knife attacks on multiple members of a family after
    petitioner was caught stealing tires, an incident in which
    Cite as 362 Or 236 (2017)	247
    petitioner rammed his vehicle into two police cars while try-
    ing to elude their pursuit, and an occasion when petitioner
    attacked a deputy sheriff in a county jail.
    Although defense counsel cross-examined Suckow,
    he did not offer expert psychological testimony to rebut
    Suckow’s testimony and diagnosis of petitioner. The only
    witness whom defense counsel called was petitioner’s wife.
    In closing argument, the prosecutor emphasized
    that the determination of whether petitioner suffered from a
    personality disorder as described in the dangerous offender
    statute was a matter for the jury, not the expert, to decide. He
    noted petitioner’s lengthy criminal history, and he pointed
    out that the gaps in that history were during periods of time
    when petitioner was imprisoned.
    Defense counsel’s closing argument focused on
    Suckow’s testimony and the prosecution’s burden of proof.
    Defense counsel pointed out that Suckow had acknowledged
    that he accepted the DSM-IV-TR criteria for conduct disor-
    der, but that (1) Suckow lacked any basis for concluding that
    petitioner had initiated the fights he had been in, (2) Suckow
    had not documented more than one instance of petitioner
    running away from home, and (3) Suckow’s report revealed
    instances of truancy only after petitioner had left St. Mary’s
    at the age of 13 or 14. Defense counsel argued that on mat-
    ters when Suckow “had to draw certain conclusions, he was
    saying he did not have the facts to support him. But he then
    kind of said he was assuming, as an adult, it’s probable,
    maybe, it was there as a child—recall that? ‘Probable’ is not
    beyond a reasonable doubt.” Defense counsel also noted that
    the jury was not bound by Suckow’s opinion, and he urged
    the jury to use the criteria from the DSM-IV-TR to conclude
    that the criteria for a conduct disorder had not been met and
    that, therefore, “[t]he antisocial behavior, then is not there
    either.”
    After closing arguments, the trial court instructed
    the jury to make findings as to whether petitioner was “suf-
    fering from a severe personality disorder indicating a pro-
    pensity toward crimes that seriously endanger the life or
    safety of another and that, because of the dangerousness
    248	                                     Richardson v. Belleque
    of [petitioner], an extended period of confined correctional
    treatment or custody is required for the protection of the
    public.” ORS 161.725(1). The court also included an instruc-
    tion that the jury was not required to accept the opinions
    of experts. The jury unanimously found that petitioner suf-
    fered from a severe personality disorder indicating a pro-
    pensity toward crimes that seriously endanger the life or
    safety of another.
    C.  The Post-Conviction Proceeding
    Petitioner initiated the present proceeding, alleging
    that his defense counsel in the underlying criminal proceed-
    ing had provided inadequate assistance of counsel, in viola-
    tion of Article I, section 11, of the Oregon Constitution. As
    pertinent here, petitioner alleged:
    “Defense counsel failed to conduct an investigation to sup-
    port his decision not to obtain a defense psychological evalu-
    ation of petitioner to rebut testimony by prosecution expert,
    Dr. George Suckow, that petitioner suffered from an anti-
    social personality disorder. A defense psychologist would
    have provided testimony that petitioner does not meet the
    diagnostic criteria for an antisocial personality disorder
    and that petitioner did not suffer from a severe personality
    disorder. As a result of counsel’s failure to retain a defense
    psychologist the jury relied exclusively upon the testimony
    of Dr. Suckow to determine that petitioner did suffer from
    a severe personality disorder. Petitioner was thereafter
    sentenced as a dangerous offender under ORS 161.725. An
    attorney exercising reasonable professional skill and judg-
    ment would have retained a psychologist for the reasons
    outlined above.”
    In support of that claim, petitioner introduced a writ-
    ten report from a clinical psychologist, Dr. Norvin Cooley. In
    his written report, Cooley indicated that he had been hired
    to evaluate petitioner and examine records to determine if
    “there were factors that should have been considered by the
    [jury] which were not provided in [petitioner’s] defense that
    could have influenced the [jury’s] opinion as to whether or
    not [petitioner] was a dangerous offender.” His record review
    covered (1) the presentencing investigation that had been
    done before petitioner’s dangerous offender hearing; (2) peti-
    tioner’s records at St. Mary’s Home for Boys; (3) Suckow’s
    Cite as 362 Or 236 (2017)	249
    report and testimony; and (4) the prosecutor’s and defense
    counsel’s opening and closing arguments at the dangerous
    offender hearing. Cooley further noted that he and other psy-
    chologists in Oregon would have been available as defense
    experts at the time of petitioner’s dangerous-offender hear-
    ing and would have obtained and reviewed critical historical
    background records concerning petitioner.
    With respect to the presentencing investigation
    report, Cooley observed that it included 14 felony convictions,
    21 misdemeanors, and a juvenile adjudication “for interstate
    transportation of a stolen vehicle [when petitioner] was 15
    years old.” Cooley further noted that the report indicated
    that petitioner had been in the Skipworth juvenile facility
    for hitting his father during a domestic violence incident
    involving both of his parents.7
    Cooley’s report also recounted numerous facts from
    his review of the St. Mary’s records.8 He indicated that the
    records showed that petitioner, after being confined in the
    Skipworth juvenile facility, had been moved to St. Mary’s in
    1965, at the age of 12. At St. Mary’s, petitioner had trouble
    getting along with other children and was easily provoked to
    anger. A caseworker note indicated that petitioner had been
    suspended from two different schools, once for “fighting,
    swearing, and truancy.” A referral letter sent to St. Mary’s
    indicated that petitioner had “run away from home on sev-
    eral occasions in May 1965” and, on one of those occasions,
    he had stolen two bicycles. But Cooley also noted that the
    St. Mary’s records revealed numerous instances of domes-
    tic violence, in particular by petitioner’s mother, leading to
    police contacts. He recounted that petitioner’s caseworkers
    at St. Mary’s had found petitioner’s mother to be “virtually
    impossible to work with” and had concluded that petitioner’s
    problems as a youth stemmed from his home life. The
    records also described numerous instances of her abusive
    behavior toward petitioner, both in public and at home. One
    of petitioner’s confinements to Skipworth was “for his own
    7
    Some evidence of that incident had been adduced during the guilt phase of
    petitioner’s trial. See 362 Or at ___.
    8
    The St. Mary’s records themselves did not come into evidence in this case.
    250	                                 Richardson v. Belleque
    protection because mother threatened to pull him from any
    foster home.”
    Cooley indicated that the St. Mary’s file included a
    number of evaluations of petitioner. As part of St. Mary’s
    screening, a psychiatrist, Robert Johnson, M.D., had seen
    petitioner. Johnson described petitioner as a “seriously dis-
    turbed youngster” who had a very difficult relationship with
    his mother. Johnson had “diagnosed [petitioner] as demon-
    strating an adjustment reaction of early adolescence with
    behavior disturbance, severe.” Johnson had thought that
    petitioner had a “poor prognosis” and likely “would be in
    conflict with authority indefinitely” but that a modification
    of his living situation “may attenuate this problem.” Cooley
    also noted that the file contained information from a psychol-
    ogist, Dr. Fischer. Fischer had found petitioner to be “very
    resistant to authority” and “unstable” but thought that, if
    petitioner developed a close relationship with a counselor,
    his prognosis would be “good.” Fischer also had noted that
    petitioner’s mother contributed significantly to petitioner’s
    resistance to authority.
    As for his review of Suckow’s testimony, Cooley char-
    acterized the testimony as “conclud[ing] by inference that
    [petitioner] must have displayed a conduct disorder.” Cooley,
    however, disagreed with Suckow on that point. Cooley
    acknowledged that the St. Mary’s records showed that peti-
    tioner’s “adjustment while there was not particularly pos-
    itive.” But highlighting the indications in the record that
    petitioner’s mother was highly abusive, Cooley opined that
    petitioner’s behavioral problems were a result of his home
    life. Cooley observed that “[t]here are other psychological,
    social, and familial issues which can create behaviors that,
    on the surface, appear antisocial when in fact they are due
    to impinging issues.” Cooley emphasized that Johnson’s psy-
    chiatric evaluation of petitioner in the St. Mary’s records—
    which Suckow had not reviewed—diagnosed petitioner
    “with an adjustment disorder, not a conduct disorder.”
    Cooley noted that his review of the case indicated
    that Suckow’s opinion had been important to the state’s
    contention that petitioner suffered from a severe person-
    ality disorder. Cooley directly rebutted Suckow’s diagnosis
    Cite as 362 Or 236 (2017)	251
    of petitioner. Cooley concluded that, if a defense expert had
    been obtained, the expert could have testified that, had
    Suckow reviewed the St. Mary’s records, Suckow would not
    have been able to accurately diagnose an antisocial person-
    ality disorder. And, Cooley opined, it would not have been
    possible, based on all of the available data, “to conclude
    that [petitioner] demonstrates the symptoms and behaviors
    consistent with the diagnosis of an antisocial personality
    disorder.”
    In response, the state offered into evidence the
    deposition of petitioner’s defense counsel, Jagger. Jagger had
    reviewed petitioner’s background and family information,
    as well as his criminal history. After reviewing Suckow’s
    report, he considered whether or not to hire an expert to
    present evidence on petitioner’s behalf at the dangerous-
    offender hearing. He could not recall whether he had talked
    to an expert about the case, but he remembered that he did
    not call an expert. He explained that he had tried approx-
    imately 20 cases involving dangerous-offender hearings in
    the past and that he sometimes used an expert but some-
    times did not. He stated that sometimes, in the minority of
    cases, “I think I can make better hay with what they had
    and they presented than confusing things by having my own
    expert.” He stated that he “did not think that there was any
    benefit to actually hir[ing] someone to do an evaluation” in
    petitioner’s case. Jagger had not obtained petitioner’s juve-
    nile records from St. Mary’s.
    In light of Jagger’s deposition testimony, the state
    argued at the post-conviction hearing that defense counsel
    had made a strategic decision not to rely on defense expert
    testimony and that his decision to rely instead on cross-
    examination of Suckow was reasonable. The state argued
    that “trial counsel did an extraordinary job in establishing
    that Dr. Suckow, by his own criteria, had not met the crite-
    ria for the diagnosis that he testified to.” The state argued
    that, had defense counsel called an expert such as Cooley to
    testify at the dangerous-offender hearing, such testimony
    “would have filled in the elements and the blanks in the
    state’s case,” such as establishing that petitioner had, in fact,
    run away from home more than once and been truant from
    252	                                      Richardson v. Belleque
    school. The state pointed out that the psychological and psy-
    chiatric evidence from the St. Mary’s records confirmed that
    petitioner had numerous behavioral problems and was very
    resistant to authority. Thus, the state asserted, bringing
    that information before the jury would, in fact, have been
    ineffective—providing the jury with additional evidence of a
    conduct disorder that existed before petitioner reached the
    age of 15.
    At the post-conviction hearing, counsel for peti-
    tioner argued that, in light of the diagnosis by the psychi-
    atrist that Cooley had found in the St. Mary’s records, “the
    jury would not have been able to legally make a determina-
    tion that [petitioner] had a severe personality disorder, an
    antisocial personality disorder, and could not therefore have
    legally, under the statutory requirements, have made the
    requisite findings for imposition of a dangerous offender sen-
    tence upon him.” Further, petitioner argued, an opinion of a
    defense psychologist that petitioner did not have a conduct
    disorder would have established that there was no antisocial
    personality disorder and, “[w]ithout an antisocial personal-
    ity disorder, the jurors could not have made their finding.”
    The post-conviction court orally ruled in favor of
    petitioner and rejected the crux of the state’s argument:
    “I think defense counsel did an excellent job with Dr. Suckow
    on cross and got as much as he could get, and it was really
    quite a bit, showing that Suckow’s diagnosis had some gaps
    in it, although the doctor still held with the same diagnosis
    even after he was impeached.
    “But what he couldn’t get on cross is that bottom line
    that says this behavior is explained through a totally
    different diagnosis that would throw out the possibility
    of dangerous offender. So if all of that behavior could be
    explained with an adjustment reactive disorder, we’re not
    in dangerous offender territory anymore.
    “I agree that Dr. Cooley had a number of facts that were
    not flattering to petitioner. * * * But all of those facts could
    then have been explained by an alternative diagnosis. And
    you can’t get there on cross.
    “So despite the very good job I think the attorney did on
    cross, it still left a hole that he could have filled by having
    Cite as 362 Or 236 (2017)	253
    his own expert. I think that was an inadequacy and I think
    this case needs to be resentenced.”
    Similarly, the post-conviction court’s written find-
    ings explain the import of petitioner’s prior adjustment reac-
    tive disorder diagnosis and refer to other circumstances of
    petitioner’s background that were unknown to defense coun-
    sel, both of which undercut Suckow’s diagnosis of petitioner:
    “Pet. found to be dangerous offender + c[ourt] sentenced
    as d[angerous] o[ffender] largely based on D.A.’s expert,
    Dr. Suckow. Trial att[orney] did not consult or call an expert.
    Suckow found that pet[itioner] had a personality disorder
    (written report says severe) which requires an underlying
    diagnosis of conduct disorder which in turn requires onset
    before age 15. He did not have pet[itioner’s] juvenile records
    from St. Mary’s that contain a diagnosis of adjustment reac-
    tive disorder not conduct disorder. This court agrees with
    att[orney] that an expert witness is not always required.
    Att[orney] did an excellent job impeaching Suckow based
    on whether or not there was a valid diagnosis of conduct
    disorder, but was unable by using cross, to bring in the
    key issue of the prior diagnosis of adjustment disorder—a
    diagnosis that would disqualify for dang[erous] off[ender].
    Dr. Cooley would have added facts that were not flattering
    to pet[itioner] but that could have been explained by the
    adj[ustment] disorder diagnosis. That diagnosis would also
    allow att[orney] to bring in details of pet[itioner’s] upbring-
    ing that were relevant and unknown to Suckow. That diag-
    nosis might well lead a court to impose a maximum guide-
    line sentence but would not have, if believed by the jury,
    have allowed a d[angerous] o[ffender] sentence.
    D.  The Court of Appeals Opinion
    The state appealed the judgment of the post-
    conviction court. In affirming, the Court of Appeals agreed
    with the post-conviction court that “counsel made his deci-
    sion to challenge Suckow’s testimony solely through cross-
    examination without properly investigating alternative
    defense strategies.” Richardson, 277 Or App at 626.
    The Court of Appeals also concluded that petitioner
    had been prejudiced by his counsel’s failure to properly
    investigate, including consulting an expert in psychology.
    Significantly, the court explained, that failure led to defense
    254	                                              Richardson v. Belleque
    counsel’s ignorance concerning petitioner’s psychological
    diagnosis when he was a boy:
    “The post-conviction court expressly found that,
    although counsel ‘did an excellent job impeaching Suckow,’
    he was ‘unable by using cross, to bring in the key issue of
    the prior diagnosis of adjustment disorder[.]’ That finding
    is supported by the evidence, and thus we are bound by
    it. Montez [v. Czerniak, 355 Or 1, 8, 322 P3d 487, adh’d to
    as modified on recons, 355 Or 598, 330 P3d 595 (2014)].
    Like Suckow, counsel did not possess petitioner’s juvenile
    mental health records from St. Mary’s, which revealed that
    petitioner had been diagnosed with an adjustment disor-
    der prior to age 15. During cross-examination, counsel did
    not question Suckow about adjustment disorders or ask
    Suckow whether the evidence suggested that petitioner
    suffered from an adjustment disorder rather than a con-
    duct disorder. Thus, although counsel was able to challenge
    Suckow’s diagnosis by highlighting a lack of evidence of
    a conduct disorder prior to age 15, he was unable during
    cross-examination to elicit testimony that petitioner might
    actually have suffered from an adjustment disorder.”
    
    Id. at 627-28.
    	        The Court of Appeals concluded that it was likely
    that the jury had relied on Suckow’s diagnosis of petitioner
    as having a conduct disorder instead of an “adjustment dis-
    order” before the age of 15, and then it turned to the DSM-
    IV-TR’s definition of “Adjustment Disorder.”9 As part of its
    analysis of prejudice, the Court of Appeals implicitly con-
    cluded that defense counsel might have called a psychologist
    like Cooley to testify and then reasoned that a jury hearing
    the testimony could have found in petitioner’s favor:
    “Had the jury accepted Cooley’s testimony over Suckow’s, it
    could have found that a diagnosis of an antisocial person-
    ality disorder was unavailable. In that case, the jury might
    not have found that petitioner had a ‘severe personality dis-
    order indicating a propensity toward crimes that seriously
    9
    The Court of Appeals did not explain why it considered petitioner’s diagno-
    sis from 1965, an “adjustment reaction of early adolescence with behavior distur-
    bance, severe,” to be identical to an “adjustment disorder” as defined in the DSM-
    IV-TR, which was published many decades later. However, Cooley had referred to
    the 1965 diagnosis as an “adjustment disorder” in his report.
    Cite as 362 Or 236 (2017)	255
    endanger the life or safety of another’ or that petitioner’s
    mental health rendered him a dangerous offender.”
    
    Id. at 629.
                            II. ANALYSIS
    A petitioner seeking post-conviction relief based on
    inadequate assistance of counsel in violation of the right to
    adequate counsel derived from Article I, Section 11, of the
    Oregon Constitution, “must prove that his or her trial coun-
    sel failed to exercise reasonable professional skill and judg-
    ment and that, because of that failure, the petitioner suf-
    fered prejudice.” Pereida-Alba v. Coursey, 356 Or 654, 661,
    342 P3d 70 (2015). We conclude that petitioner proved both
    deficient performance by defense counsel and prejudice as a
    result.
    A.  Defense Counsel’s Failure to Investigate
    This court has recently had the opportunity to
    explore the issue of inadequate assistance of counsel with
    respect to a failure to investigate expert testimony in Johnson
    v. Premo, 361 Or 688, 399 P3d 431 (2017). In that case, we
    concluded that a defense team’s failure to adequately inves-
    tigate the client’s version of the facts and to seek additional
    forensic data about the cause of the victim’s death consti-
    tuted ineffective assistance of counsel. As explained below,
    the post-conviction court’s and the Court of Appeals’ conclu-
    sions that counsel in this case failed to conduct an adequate
    investigation comports with our conclusion in Johnson.
    As we explained in Johnson, when a petitioner
    seeks to establish that counsel failed to exercise reasonable
    skill and judgment, what constitutes adequate performance
    is fact-specific and dependent on the “nature and complexity
    of the case.” 361 Or at 701; Krummacher v. Gierloff, 290 Or
    867, 873, 627 P2d 458 (1981). We further stated in Johnson
    that
    “the test for adequacy of assistance of counsel ‘allows for
    tactical choices that backfire, because, by their nature,
    trials often involve risk.’ Krummacher, 290 Or at 876. ‘[I]f
    counsel exercises reasonable professional skill and judg-
    ment, a reviewing court will not second-guess the lawyer
    in the name of the constitution, but neither will the court
    256	                                   Richardson v. Belleque
    ignore decisions made in the conduct of the defense which
    reflect an absence or suspension of professional skill and
    judgment.’ 
    Id. at 875-76.”
    Johnson, 361 Or at 702 (brackets in original). Tactical deci-
    sions, we explained, must be based on “a reasonable inves-
    tigation.” 
    Id. at 703.
    At the same time, we recognized an
    exception to that rule: “when counsel has ‘reason to believe
    that pursuing certain investigations would be fruitless or
    even harmful, counsel’s failure to pursue those investiga-
    tions may not later be challenged as unreasonable.’ ” 
    Id. at 709
    (quoting Strickland v. Washington, 
    466 U.S. 668
    , 691, 
    104 S. Ct. 2052
    , 
    80 L. Ed. 2d 674
    (1984)). Ultimately, we held that
    the petitioner’s defense counsel in Johnson rendered inade-
    quate assistance when they failed to investigate a defense
    theory suggested by their client’s account of events before
    they adopted a “wrong venue” defense that was “at best mar-
    ginally viable in the guilt phase” and that “lacked any tacti-
    cal value in the penalty phase.” 361 Or at 710.
    Our holding in Johnson is consistent with other
    “failure to investigate” cases decided by both this court and
    the United States Supreme Court. In Lichau v. Baldwin, 333
    Or 350, 360, 39 P3d 851 (2002), for example, the petitioner
    contended that his lawyer’s decision to withdraw an alibi
    defense was “not supported by an investigation of poten-
    tial alibi witnesses and military records that was reason-
    able under the circumstances.” After reviewing the limited
    investigation the lawyer undertook despite knowledge that
    should have prompted further investigation, this court con-
    cluded that the lawyer had rendered inadequate assistance.
    
    Id. at 361.
    As the court explained, “each decision to limit
    investigation of a particular defense itself must be a reason-
    able exercise of professional skill and judgment under the
    circumstances.” 
    Id. at 360.
    	        Similarly, in Wiggins v. Smith, 
    539 U.S. 510
    , 523, 
    123 S. Ct. 2527
    , 
    156 L. Ed. 2d 471
    (2003), a case in which the peti-
    tioner had been denied post-conviction relief on the ground
    that his lawyers had made a tactical decision not to inves-
    tigate his life history beyond reviewing two sets of records,
    the Supreme Court described the issue as “whether the
    investigation supporting counsel’s decision not to introduce
    Cite as 362 Or 236 (2017)	257
    mitigating evidence of Wiggins’ background was itself rea-
    sonable.” (Emphasis in original.) The Court concluded that
    the lawyers had “abandoned their investigation of peti-
    tioner’s background after having acquired only a rudimen-
    tary knowledge of his history from a narrow set of sources”
    and that, after review, reasonably competent counsel would
    have pursued leads suggested by those records as a neces-
    sary predicate “to making an informed choice among possi-
    ble defenses.” 
    Id. at 525-26;
    accord Williams v. Taylor, 
    529 U.S. 362
    , 396-97, 
    120 S. Ct. 1495
    , 
    146 L. Ed. 2d 389
    (2000) (in a
    capital-sentence case dependent on a finding of future dan-
    gerousness, holding that, in failing to investigate and dis-
    cover juvenile, social services, and prison records showing
    that the defendant was abused as a child, his limited intel-
    lectual ability, and his cooperative, nonviolent behavior in
    prison, trial counsel did not make a justifiable tactical deci-
    sion to focus on the defendant’s voluntary confession and did
    not fulfill their obligation to conduct a thorough background
    investigation).
    To address the adequacy of defense counsel’s
    investigation in this case, we must understand the nature
    and complexity of the issues presented by the dangerous-
    offender hearing. Johnson, 361 Or at 701; Krummacher,
    290 Or at 873. First, the stakes for petitioner were high
    because of the possibility of a greatly enhanced sentence if
    he were found to be a dangerous offender who suffers from a
    severe personality disorder with a propensity toward crim-
    inal activity. Second, defense counsel knew that the jury
    had already heard evidence during the guilt phase of the
    trial concerning petitioner’s extensive criminal history, his
    troubled early home life, and his confinement in numerous
    correctional institutions both as a child and as an adult.
    Third, defense counsel knew that a jury would decide the
    matter after hearing from a court-appointed psychiatrist
    who would testify adversely to petitioner, having diagnosed
    petitioner with an antisocial personality disorder. Fourth,
    defense counsel knew that the expert’s diagnosis was based
    in significant part on interpretation of petitioner’s juvenile
    history but that the expert’s diagnosis was insufficiently
    supported by the historical information contained in the
    expert’s report.
    258	                                Richardson v. Belleque
    Petitioner alleged that defense counsel had “failed
    to conduct an investigation to support his decision not to
    obtain a defense psychological evaluation of petitioner
    to rebut testimony by prosecution expert, Dr. George
    Suckow, that petitioner suffered from an antisocial per-
    sonality disorder.” In light of the nature and complexity
    of the dangerous-offender sentencing proceeding and the
    information that defense counsel knew, we agree that
    defense counsel’s decision not to investigate petitioner’s
    background as a juvenile was not a reasonable exercise of
    professional skill and judgment. Defense counsel realized
    that Suckow would rely on petitioner’s background as a
    juvenile to conclude that petitioner had a conduct disor-
    der before age 15 as part of his diagnosis that petitioner
    had an antisocial personality disorder. Yet defense coun-
    sel decided not to further investigate petitioner’s juve-
    nile background—such as securing a copy of petitioner’s
    records at St. Mary’s School for Boys—even though
    defense counsel was aware that petitioner had had a rough
    childhood and had been repeatedly exposed to domestic
    violence at home. To state it another way, defense coun-
    sel knew that the state would call Suckow to testify that
    petitioner suffers from an antisocial personality disorder,
    indicating a propensity toward criminal activity, when
    neither defense counsel nor Suckow had obtained suffi-
    cient information about petitioner’s history pertinent to
    that diagnosis. The record does not reflect that defense
    counsel even attempted to obtain additional data about
    petitioner’s juvenile history to determine the accuracy
    or inaccuracy of the historical information provided by
    Suckow. We conclude that defense counsel’s knowledge
    would lead a reasonable attorney to investigate the cli-
    ent’s juvenile history further to prepare for a hearing at
    which the client was exposed to a markedly enhanced sen-
    tence as a dangerous offender.
    We also conclude, in light of the nature and com-
    plexity of the dangerous-offender sentencing proceeding
    and the information that defense counsel knew, that defense
    counsel’s decision not to consult an expert concerning
    Suckow’s diagnosis of petitioner was not a reasonable exer-
    cise of professional skill and judgment. Although the state
    Cite as 362 Or 236 (2017)	259
    urges that defense counsel reasonably pursued a strategy
    of cross-examining Suckow to poke holes in Suckow’s diag-
    nosis, defense counsel’s choice not to obtain the assistance
    of a defense psychologist to address Suckow’s evaluation
    was not an informed one. As the Supreme Court observed
    in Wiggins, when assessing the reasonableness of counsel’s
    investigation, “a court must consider not only the quantum
    of evidence already known to counsel, but also whether the
    known evidence would lead a reasonable attorney to investi-
    gate 
    further.” 539 U.S. at 527
    .
    In State v. Huntley, 302 Or 418, 730 P2d 1234 (1986),
    this court considered the relationship between expert tes-
    timony at a dangerous-offender proceeding and the requi-
    site finding of fact that an offender suffered from a “severe
    personality disorder,” as that term is used in ORS 161.725
    (1987). Although the court concluded that the expert’s role
    is not to make the ultimate legal determination concerning
    the appropriate sentence for a defendant, Huntley, 302 Or
    at 426, and both the instructions and arguments to the jury
    in this case tracked the rule of law announced in Huntley,
    the jury nevertheless heard Suckow’s testimony that he
    had diagnosed petitioner with an antisocial personality
    disorder and his opinion that petitioner suffered from a
    severe personality disorder indicating a propensity toward
    crimes that seriously endanger the life or safety of others.
    Under Huntley, the jury was expected to “make[ ] a com-
    mon-sense decision based on as much relevant information
    as possible,” 302 Or at 426, but that is far from a simple
    task when it involves evaluation of essentially the entire
    life of an offender, in addition to data provided by an expert
    psychologist or psychiatrist pursuant to ORS 161.735(3).
    Moreover, as we have explained in the past, when expert
    testimony is introduced on a subject, there can be a danger
    that the jury “may be overly impressed or prejudiced by
    a perhaps misplaced aura of reliability or validity of the
    evidence,” thereby leading the jury “to abdicate its role of
    critical assessment.” State v. Brown, 297 Or 404, 439, 687
    P2d 751 (1984).
    That is particularly true in this case, when defense
    counsel had identified a significant flaw in Suckow’s written
    260	                                 Richardson v. Belleque
    evaluation of petitioner. As counsel’s cross-examination of
    Suckow made abundantly clear, Suckow’s report, which had
    been prepared after only a single meeting with petitioner
    and without the benefit of any psychological testing, did not
    contain enough data about petitioner’s early life to defini-
    tively establish that there was “evidence of conduct disorder
    with onset before age 15 years,” as required for a diagno-
    sis of antisocial personality disorder. See 362 Or at 244 n 5.
    But this record contains no adequate explanation as to why
    defense counsel did not undertake further investigation to
    develop the theory that Suckow’s diagnosis was incorrect
    and based on insufficient evidence. As noted above, counsel
    merely said that he believed that sometimes, in the minority
    of his cases, he found that it was preferable not to intro-
    duce expert testimony, because he could “make better hay”
    with what the state presented rather than “confusing things
    by having my own expert.” That, however, does not explain
    why defense counsel did not at least consult with an expert
    about the apparent weakness in Suckow’s diagnosis and its
    unreliability. As the post-conviction court found, defense
    counsel was unaware that petitioner had been diagnosed as
    a youth with an adjustment reactive disorder and counsel
    was unable to establish on cross-examination that, in light
    of that information, (1) petitioner’s behavior as a juvenile
    should be viewed “through a totally different diagnosis” and
    could be explained by adjustment reactive disorder after
    abuse and other conditions petitioner had suffered at home
    and (2) Suckow’s diagnosis of antisocial personality disorder
    was wrong.
    Of course, not every failure to investigate infor-
    mation that could support a viable defense strategy will
    ultimately be deemed inadequate assistance of counsel. In
    Strickland, the Court addressed the question of when it
    was permissible for counsel to curtail an investigation into
    a client’s mental health. The Court observed that strategic
    choices made after “thorough investigation of law and facts
    relevant to plausible options” do not constitute ineffective
    assistance of counsel, but strategic choices “made after less
    than complete investigation” may be reasonable only “pre-
    cisely to the extent that reasonable professional judgments
    support the limitations on investigation.” Strickland, 466 US
    Cite as 362 Or 236 (2017)	261
    at 690-91. Although Strickland concerned a death penalty
    trial and penalty-phase mitigation evidence, the context is
    similar enough to dangerous-offender sentencing that the
    case provides some guidance here.
    In Strickland, the trial attorney represented a cli-
    ent (the respondent) who confessed to multiple murders and
    other offenses and who pleaded guilty. During the plea col-
    loquy, the respondent told the judge that he had no signifi-
    cant criminal record and that he had committed the crimes
    due to the stress caused by his inability to support his fam-
    ily. The judge indicated that he respected people who took
    responsibility for their crimes. 
    Id. at 672.
    The respondent
    waived his right to a sentencing jury, and, in preparing for
    the sentencing hearing before the judge, the trial attorney
    did not seek out character witnesses or obtain a psychologi-
    cal evaluation and instead concluded that “it was advisable
    to rely on the plea colloquy for evidence about respondent’s
    background and about his claim of emotional stress.” 
    Id. at 673.
    The trial attorney knew that the respondent, despite
    his claim otherwise at the plea hearing, had an extensive
    criminal record. The trial attorney also had not observed
    the respondent to have any psychological problems, and a
    pre-plea psychological report indicated that the client had
    no major mental illness or extreme emotional disturbance.
    
    Id. at 673,
    676. By limiting the evidence on which he relied
    at sentencing, the trial attorney successfully kept out evi-
    dence of his client’s criminal record as well as the psycholog-
    ical report. 
    Id. at 673-74.
    The court nonetheless sentenced
    the respondent to death, and the respondent subsequently
    asserted that he had received inadequate assistance of coun-
    sel based on a failure to adequately investigate mitigating
    evidence and to obtain additional psychological evidence. 
    Id. at 675.
    	         The Court rejected the respondent’s arguments.
    The Court indicated that, when facts supporting a poten-
    tial line of defense are known to defense counsel, “the need
    for further investigation may be considerably diminished
    or eliminated 
    altogether.” 466 U.S. at 691
    . Ultimately, the
    Court concluded that counsel had made a reasonable stra-
    tegic choice “to argue for the extreme emotional distress
    262	                                   Richardson v. Belleque
    mitigating circumstance and to rely as fully as possible on
    respondent’s acceptance of responsibility for his crimes.” 
    Id. at 699.
    The Court observed that restricting character testi-
    mony to what came in at the plea hearing “ensured that con-
    trary character and psychological evidence and respondent’s
    criminal history, which counsel had successfully moved to
    exclude, would not come in.” 
    Id. Thus, the
    Court concluded,
    counsel had exercised reasonable professional judgment in
    preparing for the sentencing hearing.
    The present case bears some similarity to Strickland,
    but in a critical respect is different from that case. A bit like
    the trial attorney in Strickland who relied on gaps in the
    facts of record, counsel in this case had a sentencing strat-
    egy that depended, in part, on pointing out gaps in the infor-
    mation about his client’s history that Suckow used to arrive
    at a diagnosis. There is, however, a significant difference
    between this case and Strickland.
    In Strickland, the trial attorney made his decision to
    forego presenting the psychological evidence because he had
    determined—based on facts known to him from his client and
    from a prior psychological report—what the drawbacks would
    be to presenting such evidence. Here, by contrast, no evidence
    was presented that indicated that counsel knew whether pur-
    suit of additional information about petitioner’s juvenile his-
    tory would undermine or assist his defense strategy. There is
    no indication that the additional information from petitioner’s
    St. Mary’s records was already known to defense counsel
    when he decided to only cross-examine Suckow.
    Thus, although defense counsel asserted that he
    had made a calculated strategic decision that this was one
    of the minority of cases in which it was preferable not to rely
    on a defense expert, he did so without adequate knowledge
    of the underlying facts. To be a reasonable exercise of pro-
    fessional skill and judgment, a lawyer’s strategic decisions
    “must be grounded on a reasonable investigation.” Gorham
    v. Thompson, 322 Or 560, 567, 34 P3d 161 (2001). In sum,
    adequate counsel in this situation would have gained fur-
    ther information about petitioner’s psychological conditions
    and juvenile history and consulted with a defense expert
    in the field of psychology to determine how best to counter
    Cite as 362 Or 236 (2017)	263
    Suckow’s evidence that petitioner suffered from an antiso-
    cial personality disorder.
    B.  Prejudice to Petitioner
    That conclusion, however, does not end our inquiry.
    The remaining question is whether petitioner has estab-
    lished that defense counsel’s deficient performance preju-
    diced him. Trujillo v. Maass, 312 Or 431, 435, 822 P2d 703
    (1991).
    This case presents an opportunity to examine an
    issue that we had little occasion to address in Johnson: the
    nature of the test to be applied to establish prejudice in a
    “failure to investigate” case under Oregon law. Petitioner
    contends that Oregon law does not require proof of proba-
    ble, more-likely-than-not, prejudice and that he has met the
    Oregon standard of prejudice articulated in cases such as
    Krummacher, 290 Or at 883, and Stevens v. State of Oregon,
    322 Or 101, 110, 902 P2d 1137 (1995): proof that the defi-
    cient performance had “a tendency to affect the result of the
    prosecution.” Using the federal formulation of prejudice, the
    state argues that petitioner was required to prove that (1) it
    was “reasonably probable” that competent defense counsel,
    after conducting an adequate investigation and consult-
    ing an expert, would have presented the testimony of that
    expert at trial and (2) it was also “reasonably probable” that,
    with that testimony, the outcome of the hearing would have
    been different. The state argues that petitioner failed to
    meet that test.
    We begin with the proper formulation of prejudice
    under Oregon law. The state is correct that the federal for-
    mulation of prejudice in a case like this one requires the
    petitioner to prove “a reasonable probability that, but for
    counsel’s unprofessional errors, the result of the proceeding
    would have been different,” that is, a “probability sufficient
    to undermine confidence in the outcome.” 
    Strickland, 466 U.S. at 694
    . But to the extent the state suggests that peti-
    tioner was required to establish prejudice by a probability,
    or on a more-likely-than-not basis, we have rejected that
    standard. As this court explained several years ago in Green
    v. Franke, 357 Or 301, 322, 350 P3d 188 (2015), “where the
    264	                                   Richardson v. Belleque
    effect of inadequate assistance of counsel on the outcome of
    a jury trial is at issue, it is inappropriate to use a ‘probabil-
    ity’ standard for assessing prejudice.” This court indicated
    that, “because many different factors can affect the outcome
    of a jury trial, in that setting, the tendency to affect the
    outcome standard demands more than mere possibility, but
    less than probability.” 
    Id. (emphasis added).
    Although Green
    concerned a jury’s guilt-phase determination, the same is
    true when we are assessing prejudice in a case involving a
    jury deciding a sentencing issue.
    The more difficult aspect of the prejudice prong is
    how to apply the “tendency to affect the outcome” test when
    criminal defense counsel has failed to adequately investi-
    gate before proceeding with a course of action at a hearing.
    The parties and amicus curiae Oregon Criminal Defense
    Lawyers Association differ on their approach to application
    of the test.
    The state argues that the analysis of prejudice
    focuses on the ultimate effect on the jury’s determination
    and, therefore, ought to include a “preliminary step” for a
    petitioner’s proof involving an objective test: proof that “it is
    reasonably probable that a competent attorney would have
    presented the evidence” that would have been uncovered
    through an adequate investigation. In this case, the state
    contends, competent defense counsel would not have chosen
    to use the information from Cooley’s report because it would
    have undercut the cross-examination strategy and added
    factual information that would have supported Suckow’s
    testimony that petitioner suffered from a conduct disorder
    before age 15.
    In contrast, petitioner and amicus argue that
    adopting the state’s “preliminary step” would change the
    prejudice analysis in post-conviction relief cases. Petitioner
    argues that the Oregon test is “intentionally general” so
    as to cover the myriad ways that an inadequate investiga-
    tion can have an impact on the outcome, and he assumes
    that defense counsel may well have used the information
    from Cooley’s report in arguing that it would have had a
    tendency to affect the outcome of the proceeding. Amicus
    argues that the force of this court’s decision in Green
    Cite as 362 Or 236 (2017)	265
    requires us to reject the “preliminary step” argument and
    proposed test.10
    This court’s decision in Green suggests the answer
    in this case. In Green, 357 Or at 321, the court noted that
    Krummacher, which first used the phrase “tendency to
    affect the result,” was referring to the result of the prosecu-
    tion being affected by counsel’s failure to object to a ques-
    tion. The court then noted that in Stevens, the court had
    framed the inquiry in terms of a tendency to affect the out-
    come of the trial, when counsel had failed to investigate and
    discover witnesses who would impeach the complainant’s
    credibility. Green, 357 Or at 322. Thus, the state is correct
    that the “tendency to affect the outcome” standard involves
    the ultimate outcome of the proceedings as to which coun-
    sel’s deficient performance related—in this case, at least,
    the jury’s determination that petitioner was a dangerous
    offender.
    Nevertheless, in our view, the state’s argument that
    petitioner had to establish a reasonable probability that com-
    petent counsel would put on an expert like Cooley to testify
    is wrong on two levels. First, by suggesting that petitioner
    had a higher bar than proof by “more than mere possibility,”
    the state does not give Green its due. In Green, this court
    explained that when a jury determination is involved, it is
    “inappropriate to use a ‘probability’ standard for assessing
    prejudice.” 357 Or at 322. Rather, the “tendency to affect the
    outcome” standard “demands more than mere possibility,
    but less than probability.”
    Second, and more importantly, the state’s argument
    puts petitioner’s prejudice case in a figurative box, limiting
    the analysis of impact to whether reasonable defense coun-
    sel would have first called Cooley to testify as to the contents
    of his report. Although the state contends that that is solely
    10
    Petitioner also contends that the state raises its “preliminary step” argu-
    ment for the first time on appeal, to his detriment. He argues that, had he known
    of the argument, he could have provided proof that reasonable trial counsel at the
    time would have used the information at the hearing, for example, by seeking an
    admission from Jagger or else retaining an attorney expert to testify in the post-
    conviction court. Because the state questioned whether competent counsel would
    have used the Cooley information with respect to proof of the inadequate perfor-
    mance prong, petitioner’s argument concerning detriment is not well taken.
    266	                                  Richardson v. Belleque
    how petitioner litigated his case in the post-conviction court
    and defended that court’s judgment on appeal, we disagree.
    In the post-conviction court, petitioner alleged
    that defense counsel “failed to conduct an investigation to
    support his decision not to obtain a defense psychological
    evaluation of petitioner,” “failed to retain a defense psychol-
    ogist,” and failed to rebut Suckow’s testimony by a “defense
    psychologist” who “would have provided testimony that peti-
    tioner does not meet the diagnostic criteria for an antisocial
    personality disorder and that petitioner did not suffer from
    a severe personality disorder.” He alleged that, as “a result
    of counsel’s failure to retain a defense psychologist,” the
    jury “relied exclusively upon the testimony of Dr. Suckow to
    determine that petitioner did suffer from a severe personal-
    ity disorder.” In oral argument to the post-conviction court,
    petitioner’s attorney argued that it was “clear from the tran-
    scripts” that defense counsel had failed to “retain an expert
    witness” and that “his rationale” for failing to do so “doesn’t
    hold water.” He argued that problems “Suckow had attributed
    to a conduct disorder, were actually a reaction disorder from
    severe abuse that [petitioner] had suffered as a child” and
    that Suckow had not considered the records from St. Mary’s.
    Petitioner’s attorney also argued that defense counsel,
    although he tried, could not move Suckow off his diagno-
    sis of petitioner, but that “evidence was available * * * that
    he could have presented through an expert that would have
    established that [petitioner] didn’t qualify for an antisocial
    personality disorder diagnosis.” Similarly, in the Court of
    Appeals, petitioner’s lawyer argued three different theories
    of deficient performance in briefing: (1) defense counsel was
    ineffective “because he did not investigate and obtain peti-
    tioner’s ‘juvenile records from St. Mary’s that contain[ed]
    a diagnosis of adjustment reactive disorder’ ” (quoting the
    post-conviction court); (2) defense counsel was ineffective by
    failing to consult with an expert, who “ ‘would have obtained
    and reviewed historical records’ ” (quoting Cooley’s report);
    and (3) defense counsel was ineffective by failing to call an
    expert to testify at the dangerous-offender hearing.
    Based on the record, we reject the state’s argument,
    and we credit arguments by petitioner and amicus that it
    was more than a mere possibility that competent defense
    Cite as 362 Or 236 (2017)	267
    counsel could have used the information from Cooley’s report
    in ways that “could have tended to affect” the outcome of the
    dangerous-offender hearing. Green, 357 Or at 323; Lichau,
    333 Or at 365. As we have noted, “many different factors
    can affect the outcome” of a case. Green, 357 Or at 322. On
    this record, had counsel adequately investigated petitioner’s
    past and consulted a psychological expert, he would have
    obtained petitioner’s juvenile mental health records and
    would have learned that the expert could provide ammu-
    nition to oppose an enhanced dangerous-offender sentence:
    (1) an opinion critical of Suckow for failing to obtain and
    review petitioner’s records as a juvenile to support his
    diagnosis; (2) mitigation evidence that petitioner had been
    abused by his mother; (3) hard evidence that petitioner did
    not have a conduct disorder as a youth—a diagnosis by a
    psychiatrist that petitioner had an adjustment reaction of
    early adolescence; and (4) an opinion rebutting the antici-
    pated testimony from Suckow that petitioner suffered from
    an antisocial personality disorder.
    And on this record, there was “more than a mere
    possibility” that counsel could have used that information
    in cross-examining Suckow or by calling that expert to the
    stand or doing both. Competent counsel could have used
    Suckow’s failure to obtain the St. Mary’s records or other
    additional data to show that Suckow had not been thor-
    ough in reaching his opinion. Competent counsel also could
    have confronted Suckow with the diagnosis by psychiatrist
    Johnson that petitioner had an adjustment reaction of early
    adolescence, without necessarily calling a defense expert
    witness, to shut down Suckow’s explanation to the jury that
    there was indirect evidence that petitioner had a conduct
    disorder before age 15. Competent counsel also could have
    presented a defense expert’s testimony, to provide the jury
    with the information that counsel would have learned upon
    investigation and consultation, including a direct rebuttal of
    Suckow’s diagnosis and an explanation of petitioner’s con-
    duct that was not as damaging as an antisocial personality
    disorder.11
    11
    And, petitioner adds, even apart from using the information at the hear-
    ing, competent counsel could have used the information gained from Cooley
    to try to avoid a dangerous-offender hearing at all and to gain advantage in
    268	                                             Richardson v. Belleque
    Given the uses to which counsel could put the infor-
    mation from the Cooley report, there was more than a mere
    possibility that the jury could have rejected the state’s con-
    tention that petitioner suffered from a “severe personality
    disorder.” First, as our discussion above of the Huntley case
    and the jury instructions demonstrate, the jury fully under-
    stood that it was not bound by any expert testimony about
    diagnoses—including Suckow’s testimony. Second, Cooley
    opined in the post-conviction proceeding that Suckow could
    not legitimately have made a diagnosis of an antisocial per-
    sonality disorder on the facts presented and that petitioner
    did not have an antisocial personality disorder. As described
    above, although the St. Mary’s records contained additional
    information about petitioner’s history of truancy, running
    away from home, fighting, and stealing, all of that informa-
    tion was explained by Cooley as being consistent with adjust-
    ment disorder in light of petitioner’s life as a child, given
    the abuse in his home. Had the jury heard testimony from
    an expert like Cooley, it may well have doubted the diag-
    nosis of an antisocial personality disorder and whether the
    state had proved, beyond a reasonable doubt, that petitioner
    suffered from a severe personality disorder. See Apprendi
    v. New Jersey, 
    530 U.S. 466
    , 490, 
    120 S. Ct. 2348
    , 
    147 L. Ed. 2d
    435 (2000) (“Other than the fact of a prior conviction,
    any fact that increases the penalty for a crime beyond the
    prescribed statutory maximum must be submitted to a jury,
    and proved beyond a reasonable doubt.”). Accordingly, we
    conclude that there was more than a mere possibility that
    counsel’s failure to investigate petitioner’s past and consult
    with a defense expert about Suckow’s expert report could
    have tended to affect the outcome of the dangerous-offender
    proceeding.
    The decision of the Court of Appeals and the judg-
    ment of the circuit court are affirmed.
    petitioner’s sentencing. For example, he argues, competent counsel might have
    first attempted to persuade Suckow and the prosecutor to change their minds
    about petitioner’s diagnosis and to negotiate with the prosecutor for a different
    sentence for petitioner before the scheduled hearing.