Casey Clarkson v. Alaska Airlines, Inc. ( 2023 )


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  •                     FOR PUBLICATION
    UNITED STATES COURT OF APPEALS
    FOR THE NINTH CIRCUIT
    CASEY CLARKSON,                                   No. 21-35473
    Plaintiff-Appellant,          D.C. No. 2:19-cv-
    00005-TOR
    v.
    ALASKA AIRLINES, INC.;                              OPINION
    HORIZON AIR INDUSTRIES, INC.,
    Defendants-Appellees.
    Appeal from the United States District Court
    for the Eastern District of Washington
    Thomas O. Rice, District Judge, Presiding
    Argued and Submitted October 21, 2022
    Portland, Oregon
    Before: Richard A. Paez and Bridget S. Bade, Circuit
    Judges, and Haywood S. Gilliam, Jr., * District Judge.
    Opinion by Judge Paez
    *
    The Honorable Haywood S. Gilliam, Jr., United States District Judge
    for the Northern District of California, sitting by designation.
    2               CLARKSON V. ALASKA AIRLINES, INC.
    SUMMARY **
    Labor Law
    The panel reversed the district court’s grant of summary
    judgment in favor of defendants Alaska Airlines, Inc., and
    Horizon Air Industries, Inc., and remanded, in a class action
    brought under the Uniformed Services Employment and
    Reemployment Rights Act (USERRA) by Casey Clarkson,
    a commercial airline pilot and military reservist.
    Clarkson alleged that because the airlines provided paid
    leave for non-military leaves, including jury duty,
    bereavement, and sick leave, the airlines were also required
    to pay pilots during short-term military leaves of thirty days
    or less.
    Under USERRA § 4316(b)(1), “a person who is absent
    from a position of employment by reason of service in the
    uniformed services” shall be “deemed to be on furlough or
    leave of absence” and shall be “entitled to such other rights
    and benefits not determined by seniority as are generally
    provided by the employer” to other employees on non-
    military furloughs or leaves of absence. Under 
    20 C.F.R. § 1002.150
    , the “non-seniority rights and benefits to which an
    employee is entitled during a period of service are those that
    the employer provides to similarly situated employees.” If
    the benefits vary according to the type of leave, the
    employee must be given “the most favorable treatment
    accorded to any comparable form of leave when he or she
    **
    This summary constitutes no part of the opinion of the court. It has
    been prepared by court staff for the convenience of the reader.
    CLARKSON V. ALASKA AIRLINES, INC.              3
    performs service in the uniformed services.” To determine
    whether types of leave are comparable, the duration of the
    leave must be considered, as well as the purpose of the leave
    and the ability of the employee to choose when to take the
    leave.
    The panel held that the district court erred in concluding
    that no reasonable jury could find military leave comparable
    to non-military leave. In reaching this conclusion, the
    district court erred by comparing all military leaves, rather
    than just the short-term military leaves at issue here, with the
    comparator non-military leaves. The district court also erred
    by disregarding factual disputes about each of the three
    factors in the comparability analysis: duration, purpose, and
    control. The panel held that because factual disputes
    existed, comparability was an issue for the jury.
    The panel therefore reversed and remanded. It instructed
    that on remand, the district court should consider in the first
    instance the issue whether “pay during leave” was a
    standalone benefit that the airlines provided under their
    collective bargaining agreements to any employee on leave.
    4            CLARKSON V. ALASKA AIRLINES, INC.
    COUNSEL
    Jonathan E. Taylor (argued), Deepak Gupta, Peter Romer-
    Friedman, and Robert Friedman, Gupta Wessler PLLC,
    Washington, D.C.; Adam T. Klein and Michael J. Scimone,
    Outten & Golden LLP, New York, New York; Vincent
    Chang, Block & Leviton LLP, San Francisco, California; R.
    Joseph Barton and Colin M. Downes, Block & Leviton LLP,
    Washington, D.C.; Matthew Z. Crotty, Crotty & Son Law
    Firm PLLC, Spokane, Washington; Thomas G. Jarrard, The
    Law Office of Thomas G. Jarrard PLLC, Spokane,
    Washington; for Plaintiff-Appellant.
    Anton Metlitsky (argued), Mark W. Robertson, and Charles
    Mahoney, O’Melveny & Myers LLP, New York, New York;
    Jason Zarrow, O’Melveny & Myers LLP, Los Angeles,
    California; Tristan Morales, O’Melveny & Myers LLP,
    Washington, D.C.; Steven W. Fogg, Corr Cronin LLP,
    Seattle, Washington; Kathryn S. Rosen, Davis Wright
    Tremaine LLP, Seattle, Washington; for Defendants-
    Appellees.
    David T. Raimer and Douglas W. Hall, Jones Day,
    Washington, D.C., for Amicus Curiae Airlines for America.
    CLARKSON V. ALASKA AIRLINES, INC.             5
    OPINION
    PAEZ, Circuit Judge:
    For over sixty years, our nation has encouraged military
    service by continually easing the burden on servicemembers
    who must juggle military duties with civilian jobs. In the
    Selective Training and Service Act of 1940, Congress
    ensured for the first time—but not the last—that veterans
    returning to civilian jobs would not face discrimination on
    account of their service. Over the succeeding decades, re-
    employment rights were extended to military reservists and
    National Guardsmen. These protections remain all the more
    important today, as our nation relies on an all-volunteer
    military force. Indeed, just as the draft came to an end,
    Congress expanded servicemembers’ protections in the
    Veterans’ Reemployment Rights Act of 1974. Congress
    continued its tradition of recognizing the sacrifice and
    dedication of servicemembers in 1994 by enacting the
    Uniformed Services Employment and Reemployment
    Rights Act (“USERRA”). Today, USERRA § 4316(b)(1)
    requires employers to provide employees who take military
    leave with the same non-seniority rights and benefits as their
    colleagues who take comparable non-military leaves. See 
    38 U.S.C. § 4316
    (b)(1); 
    20 C.F.R. § 1002.150
    (a).
    Casey Clarkson (“Clarkson”), a commercial airline pilot
    and military reservist, claims that his employers failed to
    abide by this rule. Clarkson alleges that because Alaska
    Airlines and Horizon Air Industries (collectively, the
    “Airlines”) provide paid leave for non-military leaves
    including jury duty, bereavement, and sick leave, the
    Airlines are also required to pay pilots during short-term
    military leaves. The district court disagreed, granting
    6                  CLARKSON V. ALASKA AIRLINES, INC.
    summary judgment to the Airlines and concluding as a
    matter of law that military leave is not comparable to any
    other form of leave offered by the Airlines. We reverse.
    I. STATUTORY BACKGROUND
    A.
    Enacted in 1994, USERRA 1 contains “the most
    expansive protection to servicemembers yet enacted . . .
    [and] entitle[s] reservists and other military personnel to
    certain employment benefits while on leave.” Travers v.
    Fed. Express Corp., 
    8 F.4th 198
    , 201 (3d Cir. 2021) (cleaned
    up). 2 USERRA serves three primary purposes: (1) “[T]o
    encourage noncareer service in the uniformed services by
    eliminating or minimizing the disadvantages to civilian
    careers and employment which can result from such
    service”; (2) “to minimize . . . disruption . . . by providing
    for the prompt reemployment of [persons performing
    military service] upon their completion of such service”; and
    (3) “to prohibit discrimination against persons because of
    their service in the uniformed services.” 
    38 U.S.C. § 4301
    .
    In short, USERRA recognizes that those who serve in the
    military should be supported, rather than penalized, for their
    service. USERRA enables servicemembers to strike a
    balance between fulfilling their military duties and civilian
    obligations, including civilian jobs, without suffering
    discrimination. See Travers, 8 F.4th at 199. While
    USERRA is “the most recent in a series of laws protecting
    1
    
    Pub. L. No. 103-353, 108
     Stat. 3149 (codified at 
    38 U.S.C. § 4301
    ).
    2
    For a fuller recounting of the history of USERRA and its predecessor
    statutes, see Travers v. Fed. Express Corp., 
    8 F.4th 198
     (3d Cir. 2021),
    and Rogers v. City of San Antonio, 
    392 F.3d 758
     (5th Cir. 2004).
    CLARKSON V. ALASKA AIRLINES, INC.                   7
    veterans’ employment and reemployment rights,” Rogers v.
    City of San Antonio, 
    392 F.3d 758
    , 762 (5th Cir. 2004),
    Congress intended USERRA to build on the rights
    established in its predecessor statutes, including the
    Selective Training and Service Act of 1940 (“STSA”), Pub.
    L. No. 783, 
    54 Stat. 885
    , 890, and the Veterans’
    Reemployment Rights Act of 1974 (“VRRA”), 
    Pub. L. No. 93-508, 88
     Stat. 1578, 1594 (codified at 
    38 U.S.C. § 2021
    ).
    See also Travers, 8 F.4th at 199-201. The “large body of
    case law that had developed under those statutes remain[s]
    in full force and effect.” Rogers, 
    392 F.3d at 762
     (quoting
    
    20 C.F.R. § 1002.2
    ). An understanding of the history of
    these protective statutes and the corresponding case law is
    thus critical to our evaluation of this case.
    USERRA’s predecessor statutes guaranteed that
    servicemembers who took leave from a civilian job for
    military service could return to that job without losing
    “seniority, status, or pay.” STSA, Pub. L. No. 783, § 8(b),
    
    54 Stat. 885
    , 890; VRRA, 
    Pub. L. No. 93-508, § 2021
    (a), 
    88 Stat. 1578
    , 1595. These rights were extended to military
    reserve members and National Guardsmen throughout the
    1950s and 1960s. See, e.g., Pub. L. No. 305, § 261(f), 
    69 Stat. 598
    , 602 (1955); 
    Pub. L. No. 86-632, § 5
    , 
    74 Stat. 467
    ,
    468 (1960); accord Monroe v. Standard Oil Co., 
    452 U.S. 549
    , 555 (1981); Rogers, 
    392 F.3d at 764
    . Reservists,
    however, did not receive “protection against discharges,
    demotions, or other discriminatory conduct once reinstated”
    until 1968. Monroe, 
    452 U.S. at 556-60
    . At that time,
    Congress enacted what became § 2021(b)(3) of the VRRA, 3
    3
    Before 1974, veterans’ re-employment rights provisions were codified
    at 
    50 U.S.C. § 459
    . These provisions were recodified without
    8               CLARKSON V. ALASKA AIRLINES, INC.
    which provides: “Any person [employed by a private
    employer] shall not be denied retention in employment or
    any promotion or other incident or advantage of employment
    because of any obligation as a member of a reserve
    component of the Armed Forces of the United States.” 
    Pub. L. No. 90-491, 82
     Stat. 790 (1968).
    Both the House and Senate Reports on the proposed
    legislation explained that § 2021(b)(3) would “assure[] that
    these reservists will be entitled to the same treatment
    afforded their coworkers without such military obligation.”
    H.R. Rep. No. 90-1303, at 3 (1968); accord S. Rep. No. 90-
    1477, at 1-2 (1968). By protecting reservists from
    discrimination, the provision would encourage voluntary
    military service. See Monroe, 
    452 U.S. at 557-60
    . In 1981,
    the Supreme Court clarified in Monroe that § 2021(b)(3)
    entitled reservists to equal, but not preferential, treatment as
    compared to their non-military coworkers. Id. at 557-66.
    Five years after the Court decided Monroe, the Third
    Circuit considered the application of § 2021(b)(3) in
    Waltermyer v. Aluminum Co., 
    804 F.2d 821
     (3d Cir. 1986).
    There, the Third Circuit concluded that a National
    Guardsman was entitled to holiday pay for a holiday that
    occurred while he was on military leave because employees
    on non-military leaves, including jury duty, bereavement
    leave, and sick leave, received holiday pay. 
    Id. at 825
    .
    Although the collective bargaining agreement limited
    holiday pay to employees who worked during the holiday
    week or employees on certain enumerated leaves (which did
    not include military leave), the court concluded that the list
    substantive change in the VRRA. See Coffy v. Republic Steel Corp., 
    447 U.S. 191
    , 194 n.2 (1980).
    CLARKSON V. ALASKA AIRLINES, INC.              9
    of enumerated leaves focused on “involuntary” leaves. 
    Id.
    Because the National Guardsman’s military leave was also
    involuntary, the court held that it would be equitable, and not
    preferential, to require the employer to provide holiday pay
    under § 2021(b)(3). Id.
    Congress later codified the Waltermyer decision in
    USERRA § 4316(b)(1), the provision at issue here. As the
    House Report on the bill explained:
    The Committee intends to affirm the decision
    in Waltermyer v. Aluminum Co. of America,
    
    804 F.2d 821
     (3d Cir. 1986) that, to the extent
    the employer policy or practice varies among
    various types of non-military leaves of
    absence, the most favorable treatment
    accorded any particular leave would also be
    accorded the military leave, regardless of
    whether the non-military leave is paid or
    unpaid.
    H.R. Rep. 103-65, pt. 1, at 33-34 (1993); accord S. Rep. 103-
    158, at 58 (1993).
    B.
    Section 4316(b)(1) expanded non-seniority employment
    benefits for servicemembers, including reservists and
    Guardsmen, who must take leave from civilian jobs to
    perform their military duties. Under § 4316(b)(1), “a person
    who is absent from a position of employment by reason of
    service in the uniformed services” shall be “deemed to be on
    furlough or leave of absence,” and shall be “entitled to such
    other rights and benefits not determined by seniority as are
    generally provided by the employer” to other employees on
    10               CLARKSON V. ALASKA AIRLINES, INC.
    non-military furloughs or leaves of absence. 
    38 U.S.C. § 4316
    (b)(1). 4
    The Department of Labor’s (“DOL”) implementing
    regulation for § 4316(b)(1) explains that the “non-seniority
    rights and benefits to which an employee is entitled during a
    period of service are those that the employer provides to
    similarly situated employees by an employment contract,
    agreement, policy, practice, or plan in effect at the
    employee’s workplace.” 
    20 C.F.R. § 1002.150
    (a). The
    regulation then explains that if the benefits vary according to
    the type of leave, the employee must be given “the most
    favorable treatment accorded to any comparable form of
    leave when he or she performs service in the uniformed
    services.” 
    Id.
     at § 1002.150(b) (emphasis added). The
    regulation also explains how to determine if types of leave
    are comparable:
    To determine whether any two types of leave
    are comparable, the duration of the leave may
    be the most significant factor to compare.
    For instance, a two-day funeral leave will not
    be “comparable” to an extended leave for
    service in the uniformed service. In addition
    to comparing the duration of the absences,
    4
    Under USERRA, the term “rights and benefits” is defined as “the terms,
    conditions, or privileges of employment, including any advantage, profit,
    privilege, gain, status, account, or interest (including wages or salary for
    work performed) that accrues by reason of an employment contract or
    agreement or an employer policy, plan, or practice and includes rights
    and benefits under a pension plan, a health plan, an employee stock
    ownership plan, insurance coverage and awards, bonuses, severance pay,
    supplemental unemployment benefits, vacations, and the opportunity to
    select work hours or location of employment.” 
    38 U.S.C. § 4303
    (2).
    CLARKSON V. ALASKA AIRLINES, INC.                     11
    other factors such as the purpose of the leave
    and the ability of the employee to choose
    when to take the leave should also be
    considered.
    
    Id.
     at § 1002.150(b). Clarkson challenges the Airlines’
    compliance with this regulation.
    II. DISTRICT COURT PROCEEDINGS
    Clarkson filed this action against the Airlines in 2019,
    alleging that the Airlines violated § 4316(b)(1) of USERRA
    by failing to pay pilots who took short-term military leave
    while paying pilots who took comparable non-military
    leaves. He filed the action on behalf of himself and all others
    similarly situated. The district court certified a “Paid Leave
    Class” in August 2020, defined as: “All current or former
    Alaska or Horizon pilots who have taken short-term military
    leave from October 10, 2004 through the date of the
    judgment.” Although the certification order did not define
    short-term military leave, the parties and court understood it
    to mean military leaves of thirty days or less. Clarkson and
    the members of the class were or are employed as pilots by
    Alaska or Horizon. While employed, Clarkson and the other
    class members took at least one military leave of thirty days
    or less. These facts are undisputed.
    What the parties cannot agree on, however, is whether
    short-term military leave is comparable to the non-military
    leaves offered by the Airlines, namely jury duty,
    bereavement leave, or sick leave. 5 In seeking summary
    5
    Clarkson also argues that vacation leave may be comparable to short-
    term military leave. The Airlines do not address vacation leave, asserting
    that such argument is precluded because Clarkson did not specifically
    identify vacation leave as a comparator in his complaint. Clarkson’s
    12               CLARKSON V. ALASKA AIRLINES, INC.
    judgment, the Airlines argued that military leave is not
    comparable to non-military leave as a matter of law. In the
    alternative, the Airlines argued that even if the leaves were
    comparable, “pay during leave” is not a benefit offered in
    their collective bargaining agreements (“CBAs”) to which
    the class members are entitled. Clarkson did not address this
    second argument, and instead argued that a reasonable jury
    could find that some or all of the non-military leaves offered
    by the Airlines are comparable to short-term military leave.
    As in the district court, the parties’ arguments focus on
    the three comparability factors outlined in the regulation: (1)
    duration of leave, (2) purpose of leave, and (3) ability of the
    employee to choose when to take the leave (also referred to
    as “control”). 
    20 C.F.R. § 1002.150
    (b). In the district court,
    each side submitted an expert report comparing the duration
    of military leave to the duration of other types of leave. The
    Airlines’ expert conducted his analysis using all military
    leaves rather than just short-term military leaves of thirty
    days or less, analyzed the frequency of leaves, and focused
    on the length of leaves at the highest percentiles rather than
    the average lengths. As a result, his comparator numbers
    look quite different from the numbers produced by
    Clarkson’s expert, who focused on the average, mode, and
    median days taken of short-term military leave. The parties
    complaint repeatedly references “other” types of leave besides jury duty,
    bereavement, and sick leave, and Clarkson included vacation as a
    comparator leave in his opposition to summary judgment. However, the
    district court did not address vacation leave as a comparator. Because it
    is clear that a reasonable jury could find jury duty, bereavement, or sick
    leave comparable to short-term military leave, we need not address
    vacation leave to reverse the grant of summary judgment. On remand,
    the district court may address vacation leave as a comparator in the first
    instance.
    CLARKSON V. ALASKA AIRLINES, INC.        13
    also presented conflicting evidence about the purpose of
    military leave and the ability of pilots to control when they
    take such leave. The Airlines contend that pilots take
    military leave to pursue a parallel career, while Clarkson
    maintains that military leave allows pilots to perform a civic
    duty and public service. The Airlines also contend that pilots
    have near total control over when to take military leave,
    while Clarkson argues that the military schedule is not so
    flexible.
    On each factor, the district court determined there were
    no genuine issues of material fact and concluded that
    military leave is not comparable to any other leave as a
    matter of law. The district court thus did not address the
    “pay during leave” issue and granted summary judgment to
    the Airlines. Clarkson timely appealed. 6 We reverse.
    III. STANDARD OF REVIEW
    We review de novo a district court’s summary judgment
    ruling to determine whether “there are any genuine disputes
    of material fact and whether the district court correctly
    applied the relevant substantive law.” Reynaga v. Roseburg
    Forest Products, 
    847 F.3d 678
    , 685 (9th Cir. 2017) (quoting
    Dominguez-Curry v. Nevada Trans. Dep’t, 
    424 F.3d 1027
    ,
    1033 (9th Cir. 2005)). “An issue of fact is genuine ‘if the
    evidence is such that a reasonable jury could return a verdict
    for the nonmoving party.’” Id. at 685-86 (quoting Villiarimo
    v. Aloha Island Air, Inc., 
    281 F.3d 1054
    , 1061 (9th Cir.
    2002)). A grant of summary judgment is “proper only where
    there is no genuine issue of any material fact or where
    viewing the evidence and the inferences which may be
    drawn therefrom in the light most favorable to the adverse
    6
    We have jurisdiction under 
    28 U.S.C. § 1291
    .
    14             CLARKSON V. ALASKA AIRLINES, INC.
    party, the movant is clearly entitled to prevail as a matter of
    law.” Sandvik v. Alaska Packers Ass’n, 
    609 F.2d 969
    , 974
    (9th Cir. 1979) (quoting Smith v. Gross, 
    604 F.2d 639
    , 641
    (9th Cir. 1979)). As we discuss below, the district court
    failed to heed these summary judgment principles in its
    comparability analysis.
    IV. DISCUSSION
    In entering judgment for the Airlines, the district court
    concluded that no reasonable jury could find military leave
    comparable to non-military leave.           In reaching this
    conclusion, the district court erred by comparing all military
    leaves, rather than just the short-term military leaves at issue
    here, with the comparator non-military leaves. The court
    also erred by disregarding countless factual disputes about
    each of the three factors in the comparability analysis:
    duration, purpose, and control. The court seemingly
    considered only the evidence presented by the Airlines when
    it concluded no reasonable jury could find for Clarkson.
    Because factual disputes exist, comparability is an issue for
    the jury.
    A. Under USERRA, Courts Must Consider the
    Length of Leave at Issue
    In concluding that military leave is not comparable to
    other leaves as a matter of law, the district court first agreed
    with the Airlines that military leave must be considered as a
    “general category of leave,” Clarkson v. Alaska Airlines,
    Inc., 
    2021 WL 2080199
    , at *4 (E.D. Wash. May 24, 2021),
    rather than in an “individualized analysis.” 
    Id. at *5
    . The
    district court thus decided that all military leaves taken by
    pilots at the Airlines—whether two days or two years—must
    be grouped together when assessing the most significant
    comparability factor: duration. 
    20 C.F.R. § 1002.150
    (b).
    CLARKSON V. ALASKA AIRLINES, INC.            15
    Although we have not yet addressed whether military
    leave should be considered based on its length or
    categorically when assessing USERRA violations, we hold
    that examining the length of leave at issue is the correct
    approach. Cf. Paige v. California, 
    291 F.3d 1141
    , 1147 (9th
    Cir. 2002) (determining the proper comparator groups is a
    question of law). The plaintiff, as master of the complaint,
    can limit the request for recovery of benefits to specific,
    shorter military leaves. To follow the district court’s
    approach and consider military leaves categorically would
    render USERRA’s protections meaningless. Military leaves
    vary greatly in length, and the longest leaves can last years.
    Were we to adopt a categorical approach to military leaves,
    no other type of leave would look similar, and
    servicemembers would not be protected under § 4316(b)(1).
    Indeed, the statute’s implementing regulation suggests
    that the military leave at issue should be compared with the
    alleged comparable leaves. Section 1002.150 states that
    duration is the most significant factor to compare when
    determining if “any two types of leave are comparable.” In
    context, “any two types of leave” must refer to (1) military
    leave and (2) another employer-offered leave. As the
    regulation explains, “a two-day funeral leave will not be
    ‘comparable’ to an extended leave for service.” 20 C.F.R.
    1002.150(b). But while an “extended” military leave is not
    comparable to a “two-day funeral leave,” it is entirely
    possible that a two-day military leave is comparable to a
    two-day funeral leave.
    Although our sister circuits have not addressed this
    question directly, their opinions support the conclusion that
    a plaintiff may define his claim by the particular length of
    the military leave at issue. As the Seventh Circuit explained:
    “It is up to the employee to demonstrate that any given
    16               CLARKSON V. ALASKA AIRLINES, INC.
    stretch of military leave is comparable to a form of
    nonmilitary leave that is accorded a benefit.” White v.
    United Airlines, Inc., 
    987 F.3d 616
    , 624 (7th Cir. 2021)
    (emphasis added). 7
    We thus conclude that the district court erred when it
    compared non-military leaves offered by the Airlines to all
    military leaves taken by pilots at the Airlines. Clarkson
    limited his claim to military leaves of thirty days or less.
    Thus, the relevant question is whether such short-term leaves
    are comparable to the other leaves offered by the Airlines.
    As discussed next, this is a question for the jury.
    B. Whether Short-Term Military Leave Is
    Comparable to Other Types of Leaves Is a Jury
    Question
    “Comparability is a question of fact.” Syufy Enters. v.
    Am. Multicinema, Inc., 
    793 F.2d 990
    , 1003 (9th Cir. 1986).
    It is thus a question for the jury unless “the facts of a case
    suggest that no reasonable jury could see enough
    commonality for a meaningful comparison.” Howell v.
    7
    The district court acknowledged White but stated it “is not inclined to
    apply the Seventh Circuit’s White holding to this case, as the Ninth
    Circuit has not yet spoken on the issue.” Clarkson, 
    2021 WL 2080199
    at *5. The Fifth Circuit has also denied summary judgment in a similar
    § 4316(b)(1) case, noting that there “are genuinely disputable issues as
    to the material facts of whether involuntary non-military leaves, not
    generally for extended durations . . . are comparable to each plaintiff’s
    military leaves taken for service in the uniformed services.” Rogers, 
    392 F.3d at 771-72
     (emphasis added); see also Tully v. Dep’t of Just., 
    481 F.3d 1367
    , 1368 (Fed. Cir. 2007) (holding that employee was not entitled
    to holiday pay because a two-and-a-half-year military leave was not
    comparable to other leaves); Waltermyer, 
    804 F.2d at 825
     (holding that
    employee was entitled to holiday pay because a two-week military leave
    was comparable to other leaves).
    CLARKSON V. ALASKA AIRLINES, INC.             17
    Wexford Health Sources, Inc., 
    987 F.3d 647
    , 657 (7th Cir.
    2021) (quoting Rozumalski v. W.F. Baird & Assocs., Ltd.,
    
    937 F.3d 919
    , 927 (7th Cir. 2019)) (holding that
    comparability in employment discrimination cases is a jury
    question); see also Wheeler v. Georgetown Univ. Hosp., 
    812 F.3d 1109
    , 1116 (D.C. Cir. 2016) (same); Graham v. Long
    Island R.R., 
    230 F.3d 34
    , 39 (2d Cir. 2000) (same).
    The district court considered the three factors outlined in
    the regulation—duration, purpose, and control—and found
    that no jury could find in Clarkson’s favor given “significant
    differences” between military leave and non-military leave
    as to each factor. The district court thus granted the Airlines
    summary judgment because it found that there “are no
    genuine issues of material fact as to whether military leave
    is comparable to other forms of leave covered by the CBAs;
    they are not comparable.” Clarkson, 
    2021 WL 2080199
     at
    *9.
    This conclusion was erroneous. At the summary
    judgment stage, “the judge’s function is not . . . to weigh the
    evidence and determine the truth of the matter[,] but to
    determine whether there is a genuine issue for trial.”
    Anderson v. Liberty Lobby, Inc., 
    477 U.S. 242
    , 249 (1986).
    As explained below, the record evidence presents genuine
    issues of material fact as to each factor that, when viewed in
    the light most favorable to Clarkson, would allow a
    reasonable jury to find in his favor.
    1. Duration
    Duration is the “most significant factor” in the
    comparability analysis. 
    20 C.F.R. § 1002.150
    (b). After
    considering the evidence, the district court determined that
    “[g]iven the significant differences in duration and
    frequency, military leave is not comparable to jury duty,
    18             CLARKSON V. ALASKA AIRLINES, INC.
    bereavement leave, and sick leave.” Clarkson, 
    2021 WL 2080199
     at *6. This holding ignored significant factual
    disputes over the leave data presented by the Airlines. The
    district court’s analysis was also flawed by including
    frequency as an integral factor in the duration analysis.
    a. Disputed statistical evidence
    Although the parties agree on the underlying dataset
    regarding the duration of military and non-military leaves,
    their agreement ends there. Each side’s expert used that
    dataset to present different opinions on the comparability of
    the duration of military and non-military leave. When
    parties “offer conflicting inferences drawn from the
    [statistical] evidence . . . there is a genuine dispute of
    material fact . . . and [the] action must proceed to trial.”
    Paige, 
    291 F.3d at 1147
    . It is for the jury, not the court, to
    decide how to weigh these conflicting inferences. Tyson
    Foods, Inc. v. Bouaphakeo, 
    577 U.S. 442
    , 459 (2016) (“Once
    a district court finds evidence to be admissible, its
    persuasiveness is, in general, a matter for the jury.”); City of
    Pomona v. SQM N. Am. Corp., 
    750 F.3d 1036
    , 1049 (9th Cir.
    2014) (“Where two credible experts disagree, it is the job of
    the fact finder, not the trial court, to determine which source
    is more credible and reliable.”).
    Instead of recognizing this factual dispute, the district
    court adopted the Airlines’ evidence and granted their
    motion for summary judgment. In its analysis of the parties’
    arguments, the court failed to consider the evidence in the
    light most favorable to Clarkson. Instead, the court relied
    only on the Airlines’ statistical evidence. This is evident
    from the district court’s repeated references to the Airlines’
    Reply Statement of Material Facts, including to several facts
    that Clarkson disputes or materially clarifies. Further, as
    CLARKSON V. ALASKA AIRLINES, INC.                    19
    discussed below, the district court’s review of the statistical
    evidence was tainted by its decision to consider military
    leave categorically.
    To conclude that the leaves are incomparable, the district
    court compared the longest military leave (185 days at
    Alaska, excluding the 99th percentile, and 70 days at
    Horizon, excluding the 95th percentile) with the longest jury
    duty leave (6 days at Alaska and 5 days at Horizon), the
    longest bereavement leave (6 days at Alaska and 3 days at
    Horizon), and the longest sick leave (5 days at Alaska and 4
    days at Horizon). 8 But Clarkson presented a different
    analysis of the data in his opposition to summary judgment.
    His analysis showed that Alaska pilots took an average of
    3.10 days of short-term military leave, 2.94 days of jury duty
    leave, 2.77 days of bereavement leave, and 2.52 days of sick
    leave. 9 Horizon pilots took an average of 4.23 days of short-
    term military leave, 2.66 days of jury duty leave, 2.48 days
    of bereavement leave, and 2.17 days of sick leave. 10 The
    8
    The jury duty and bereavement leave data presented by the Airlines
    covers the period between October 2004 and December 2020 for Alaska
    pilots and between October 2008 and December 2020 for Horizon pilots.
    The military leave data described above is from those time periods. The
    sick leave data, however, only covers the period from September 2013
    to December 2020 for Alaska pilots and from February 2010 to
    December 2020 for Horizon pilots. During those periods, the
    comparable longest military leave is 122 days for Alaska pilots
    (excluding the 99th percentile) and 58 days for Horizon pilots (excluding
    the 95th percentile).
    9
    Again, because the sick leave data covered a different time period, the
    comparable average short-term military leave from September 2013 to
    December 2020 is 2.50 days for Alaska pilots.
    10
    The comparable average short-term military leave from February 2010
    to December 2020 is 4.23 days for Horizon pilots.
    20            CLARKSON V. ALASKA AIRLINES, INC.
    mode and median days of short-term military leave appear
    even more similar to the mode and median days of non-
    military leaves. The district court did not mention nor
    discuss Clarkson’s analysis. Nor did the district court
    mention the Airlines’ expert’s finding that the longest short-
    term military leave, which is the appropriate comparator,
    was 6 days for Alaska pilots and 9 days for Horizon pilots
    (excluding the 90th percentiles). Using these statistical
    measures, a reasonable jury could find in Clarkson’s favor.
    As noted above, summary judgment is only appropriate
    “where viewing the evidence and the inferences which may
    be drawn therefrom in the light most favorable to the adverse
    party, the movant is clearly entitled to prevail as a matter of
    law.” Sandvik, 
    609 F.2d at 974
     (quoting Smith, 
    604 F.2d at 641
    ). Here, the evidence put forth by Clarkson—and by the
    Airlines—could allow a jury to infer that the duration of
    military leave is comparable to the duration of jury duty,
    bereavement, or sick leave. The district court erred in
    concluding otherwise.
    b. Frequency
    The district court’s decision is also flawed because it
    treated frequency as an integral part of the duration analysis.
    As the court put it, “frequency is useful in the duration
    analysis.” Clarkson, 
    2021 WL 2080199
     at *5. While it is
    true that the implementing regulation leaves room for courts
    to consider factors besides duration, purpose, and control,
    see 
    20 C.F.R. § 1002.150
    (b) (“[O]ther factors such as
    [purpose and control] should also be considered.” (emphasis
    added)), the factors enumerated in the regulation should be
    weighed most heavily when considering whether two leaves
    are comparable. Cf. Sanders v. City of Newport, 
    657 F.3d 772
    , 780-81 (9th Cir. 2011) (interpreting federal labor statute
    CLARKSON V. ALASKA AIRLINES, INC.                      21
    “in light of the text of the pertinent DOL regulations”).
    Section 1002.150(b) instructs that duration is the “most
    significant” factor in the comparability analysis, and it does
    not mention frequency. See 
    20 C.F.R. § 1002.150
    (b).
    Frequency is not encompassed within duration. Rather, the
    two terms convey distinct concepts. Duration is “the time
    during which something exists or lasts.” Merriam-Webster
    Dictionary,                            https://www.merriam-
    webster.com/dictionary/duration (2022). Frequency is “the
    number of repetitions of a periodic process in a unit of time.”
    Merriam-Webster         Dictionary,    https://www.merriam-
    webster.com/dictionary/frequency (2022).
    Including frequency in the duration analysis effectively
    undermines the purpose of USERRA. 11 Congress intended
    USERRA and its predecessor statutes to protect reservists
    during their “frequent absences from work” with the full
    understanding that those frequent absences could “cause
    considerable inconvenience to an employer.” Monroe, 
    452 U.S. at 565
    . Nevertheless, “Congress has provided . . . that
    employers may not rid themselves of such inconveniences
    and productivity losses by discharging or otherwise
    disadvantaging employee-reservists solely because of their
    military obligations.” 12 
    Id.
    11
    This error is especially significant given the “canon that provisions for
    benefits to members of the Armed Services are to be construed in the
    beneficiaries’ favor.” King v. St. Vincent’s Hosp., 
    502 U.S. 215
    , 220 n.9
    (1991) (citing Fishgold v. Sullivan Drydock & Repair Corp., 
    328 U.S. 275
    , 285 (1946)).
    12
    Regulations implementing other provisions of USERRA also
    explicitly state that “the timing, frequency, and duration of [a] person’s
    training or service . . . shall not be a basis for denying protection.” 
    38 U.S.C. § 4312
    (h) (emphasis added).
    22             CLARKSON V. ALASKA AIRLINES, INC.
    In justifying the use of frequency, the Airlines rely on the
    very rationale that Congress sought to prohibit: “The fact
    that military duty leave happens much more frequently . . .
    than, say, jury duty leave, means that providing paid military
    leave is substantially more costly and burdensome to
    operations than providing paid jury duty leave.” But
    Congress enacted USERRA to “prohibit discrimination
    against persons because of their service in the uniformed
    services,” 
    38 U.S.C. § 4301
    , regardless of whether those
    anti-discrimination protections increase employers’ costs
    and burdens. See S. Rep. No. 90-1477, at 1 (explaining the
    statute was intended to protect reservists who were
    discriminated against because of frequent obligations).
    The Airlines also attempt to justify the use of frequency
    by arguing that “frequency is highly relevant in this case due
    to the peculiar military leave patterns unique to pilots,” who
    allegedly take more frequent leaves than other military
    reservists. But USERRA is no less protective of pilots than
    of any other military reservist.
    The Airlines’ (and amicus’s) policy arguments that pilots
    will use their frequent military duties to intentionally create
    conflicts to garner double pay, or that airlines will eliminate
    benefits such as paid bereavement leave or paid jury duty
    leave to avoid paying for military leave, are not compelling.
    The Airlines are only required to provide equal treatment,
    not preferential treatment, to employees taking military
    leave. Thus, if the employer only provides three days of paid
    bereavement leave per year or only offers the difference in
    pay between the employee’s salary and the compensation for
    jury duty (as Horizon does), that is all the employer would
    be required to provide to the servicemember. We are thus
    unpersuaded by the Airlines’ arguments that a ruling in
    CLARKSON V. ALASKA AIRLINES, INC.             23
    Clarkson’s favor would drastically increase costs or
    convince employers to cease offering other paid leaves.
    2. Purpose
    In considering the purpose factor, the district court found
    that “the evidence supports [the Airlines’] position that a
    significant purpose of military leave under the CBAs is to
    allow employees to pursue parallel careers.” Clarkson, 
    2021 WL 2080199
     at *7. By accepting this position, the district
    court rejected Clarkson’s evidence demonstrating that the
    primary purpose of military leave is to perform a civic duty
    and public service.
    Clarkson’s argument is both intuitive and well-supported
    by the record. In his deposition, Clarkson explained that he
    joined the military “to serve.” Alaska representatives also
    repeatedly acknowledged in their depositions and answers to
    interrogatories that public service is a primary purpose of
    military leave. Nonetheless, the Airlines attempt to
    undermine Clarkson’s testimony by pointing to a single
    question and answer from Clarkson’s deposition:
    Q: Would you consider it           accurate to
    describe military service      for Horizon
    pilots as a second career?
    A: I don’t know if we could       consider it a
    second career. I would          say parallel
    career.
    The district court, however, may not judge credibility,
    weigh the evidence, or resolve factual disputes at summary
    judgment. See Anderson, 
    477 U.S. at 255
    . The court thus
    erred when it held that there are no genuine disputes about
    24               CLARKSON V. ALASKA AIRLINES, INC.
    the purpose of military leave. 13 It is for the jury to determine
    how much weight to give to the evidence presented about the
    purpose of military leave.
    3. Control
    Finally, the district court found that “pilots have a greater
    degree of control over their ability to take military leave and
    schedule around such leave” than employees taking non-
    military leaves. Clarkson, 
    2021 WL 2080199
     at *8. In so
    finding, the district court again accepted the Airlines’ factual
    contentions and ignored Clarkson’s factual presentation.
    Given the record evidence, however, a reasonable jury could
    find that pilots do not have significantly more control over
    military duty than they do over other types of leave.
    At both Airlines, pilots bid on their monthly schedules in
    advance and must provide notice of known absences,
    including scheduled military duty, at the time of bidding.
    The scheduling systems are designed to schedule pilots to
    avoid these absences, but conflicts can still occur because
    bidding takes place by seniority. To avoid conflicts after the
    schedules are released, pilots can trade trips with other pilots
    on a voluntary basis (with some limitations) and pick up or
    drop trips (with approval). The parties agree about this basic
    process. They also agree that when a pilot is in the military,
    his or her military service is involuntary.
    The parties disagree, however, about the level of control
    that pilots have to schedule their military duty so that it does
    13
    The district court’s conclusion that the purpose of military leave is to
    promote pilots’ own individual interests in a “parallel career” makes
    little sense when military leave is protected by USERRA, which
    Congress enacted explicitly to encourage public service in the military.
    See 
    38 U.S.C. § 4301
    .
    CLARKSON V. ALASKA AIRLINES, INC.                       25
    not conflict with their work schedules at the Airlines. The
    Airlines contend that pilots have “tremendous” flexibility to
    schedule their military service, citing the testimony of
    Ronald Limes, Alaska’s Base Chief Pilot and former Air
    Force reservist. 14 In his deposition, Mr. Limes explained
    that as a commander in the reserves, he had “very little”
    flexibility, but as a rank-and-file servicemember, he had
    “tremendous” flexibility to schedule squadron trainings on
    weekends. Clarkson maintains that pilots’ control over
    military duty, especially duties beyond those squadron
    trainings, is more limited. Pilots can work with their military
    schedulers to resolve conflicts, but the ability to reschedule
    military duty depends on many factors including the pilot’s
    training requirements, military needs, and the availability of
    opportunities to engage in specific kinds of training.
    Clarkson also argues that many of the leaves at issue in this
    case were unknown to pilots more than a few weeks in
    advance, rendering pilots’ control over the scheduling
    process irrelevant. In his deposition, Clarkson explained that
    predetermined monthly military schedules would often
    change with little notice. Only the drill weekends, which
    were set annually by the governor, were unlikely to change.
    Given this factual record, the district court erred in
    finding that “[t]o the extent there is any scheduling conflict,
    pilots can . . . work with the bidding system and other pilots
    to ensure their flight schedules for [the Airlines]
    14
    The Airlines also argue that the “most pointed evidence” comes from
    Captain James Meldrum, an Alaska pilot who refused to sign a
    declaration stating: “Even if a pilot volunteers for military duty it is the
    military, not the pilot, who dictates the time and duration of that leave.”
    However, in his deposition, Captain Meldrum explained it is only his
    “belief” that military pilots have control; he has never been in the
    military himself.
    26               CLARKSON V. ALASKA AIRLINES, INC.
    accommodate their military leave schedules.” Clarkson,
    
    2021 WL 2080199
     at *8. The evidence shows that pilots can
    try to trade shifts with other pilots and that pilots can try to
    work with their military scheduler to rearrange their duty
    periods. 15 A jury could reasonably conclude that because of
    last minute assignments, pilots do not have enough control
    over their schedules to prevent conflicts. A jury could also
    find that pilots’ level of control over their military duty is
    comparable to their level of control over other types of
    leaves. For instance, pilots receive advance notice of jury
    duty and have some flexibility to reschedule it. Pilots can
    also use sick leave for pre-scheduled appointments or
    procedures. These comparability determinations are for the
    jury to make, not the court. 16
    15
    USERRA’s legislative history addresses employees’ ability to
    reschedule work, as reflected in the House Report on the bill that became
    § 4316(b)(1):
    [T]o the extent the employer policy or practice varies
    among various types of non-military leaves of
    absence, the most favorable treatment accorded any
    particular leave would also be accorded the military
    leave . . . . Thus, for example, an employer cannot
    require servicemembers to reschedule their work week
    because of a conflict with reserve or National Guard
    duty, unless all other employees who miss work are
    required to reschedule their work.
    H.R. Rep. 103-65, pt. 1, at 33-34 (1993) (citations omitted); see also
    Rogers, 
    392 F.3d at
    767-68 (citing the House Report).
    16
    Clarkson also argues that because military leave is involuntary, the
    “control” factor must come out in his favor. Clarkson relies on
    Waltermyer, which explained that military leave is comparable to jury
    duty leave, bereavement leave, and sick leave because all such leaves
    signaled “lack of choice by the employees.” 804 F.3d at 825. But, in
    CLARKSON V. ALASKA AIRLINES, INC.                     27
    ***
    As explained above, the district court improperly
    resolved factual disputes as to each factor in the
    comparability analysis in order to grant summary judgment.
    Comparability is fundamentally an issue for the jury, and
    where reasonable jurors could return a verdict in favor of the
    nonmoving party, factual disputes must be resolved by a
    jury. See, e.g., Reynaga, 
    847 F.3d at 685
     (citations omitted).
    Here, Clarkson has presented persuasive evidence in support
    of his claim. We therefore reverse the grant of summary
    judgment and remand for further proceedings consistent
    with this opinion.
    C. Pay During Leave
    Finally, the Airlines argue that “pay during leave” is not
    a standalone benefit that they provide under their CBAs to
    any employee on leave, rendering Clarkson’s claim moot
    even if short-term military leave is comparable to another
    type of leave. Because the district court found that military
    leave was not comparable to any other leaves, it did not
    address this issue and “decline[d] to adopt a specific
    interpretation of the ‘rights and benefits’ definition.”
    Clarkson, 
    2021 WL 2080199
     at *3. Although our sister
    circuits have addressed this issue, see Travers, 8 F.4th at
    199; White, 987 F.3d at 619, we remand for the district court
    Waltermyer, the court concluded that: “Particularly important is the fact
    that the guardsmen have no individual voice in selecting the weeks they
    will be on active duty.” Id. Here, the Airlines have presented evidence
    to demonstrate that pilots may have some “voice in selecting” their
    schedules. The governing regulation also clearly states that the factor to
    consider is “the ability of the employee to choose when to take the
    leave,” 
    20 C.F.R. § 1002.150
    (b), not whether the leave is voluntary.
    28            CLARKSON V. ALASKA AIRLINES, INC.
    to consider the “pay during leave” issue in the first instance.
    CONCLUSION
    For the foregoing reasons, we reverse the district court’s
    grant of summary judgment to the Airlines. On remand, the
    district court should consider the “pay during leave” issue in
    the first instance.
    REVERSED AND REMANDED.