Carpenter vs. The Boeing Company

Filing 920060807

Opinion

United States Court of Appeals Tenth Circuit PUBLISH U N IT E D ST A T E S C O U R T O F A PP E A L S T E N T H C IR C U IT

F IL E D

August 7, 2006
Elisabeth A. Shumaker Clerk of Court

K A RLA CA RPEN TER ; LIN D A W ILK ERSO N ; SH ER YL LA N DON; SA N D Y WILC YN SK I; SO N Y A PH ILLIPS; C HA RLEN E C HA PM AN; C HERYL LEE PER SIN G ER ; NENA H O LD ER ; R UB Y R YH ER D, individually & on behalf of all others sim ilarly situated; M A RY D EA N; FA ITH BR ID G EWA T ER ; V ERLENE M AHOLM ES, individually, Plaintiffs - Appellants/CrossAppellees, v. TH E BOEIN G CO M PA N Y , Defendant - Appellee/CrossAppellant. -------------------------------------K A RLA CA RPEN TER ; LIN D A W ILK ERSO N ; SH ER YL LA N DON; SA N D Y WILC YN SK I; SO N Y A PH ILLIPS; C HA RLEN E C HA PM AN; C HERYL LEE PER SIN G ER ; NENA H O LD ER ; R UB Y R YH ER D, individually, and on behalf of all other persons similarly situated, Petitioners, Nos. 04-3334, 04-3350, 04-3351

No. 04-602 v. TH E B OEIN G CO M PA N Y , Respondent.

A PPE A L S FR O M T H E U N IT ED ST A T ES D IST R IC T C O U R T FO R T H E D IST R IC T O F K A N SA S (D .C . N O . 02-C V -1019-W E B )

Jeffrey T. Sprung, Hagens Berman Sobol Shapiro LLP, argued for Plaintiffs Appellants/Cross-Appellees, (Steve W . Berman, Andrew M . Volk, Ivy D. Arai, Hagens Berman Sobol Shapiro LLP, Seattle, W ashington, and M ark B. Hutton and Derek S. Casey, Hutton & Hutton, W ichita, Kansas, with him on the brief). James M . Armstrong, Foulston Siefkin LLP, argued for D efendant Appellee/Cross-Appellant, (M ary Kathleen Babcock, Trisha A. Thelen, Carolyn L. M atthews, Foulston Siefkin LLP, W ichita, Kansas, and C. Geoffrey W eirich, Paul, Hastings, Janofsky & W alker LLP, Atlanta, Georgia, with him on the brief). M ary Dean, Faith Bridgewater and V erlene M aholmes, pro se Plaintiffs Appellants/Cross-Appellees, submitted a brief.

Before H A R T Z, A N D ER SO N , and O 'B R IE N , Circuit Judges.

H A R T Z, Circuit Judge.

Plaintiffs appeal from the district court's disposition of the em ploym entdiscrim ination claim s of female employees at the Boeing Com pany's W ichita, Kansas, facility. They have sought to bring class-action claim s alleging several -2-

unlawful employm ent practices under both disparate-im pact and disparatetreatm ent theories of discrim ination. The two subclasses relevant to this appeal are a subclass of hourly female workers (the Hourly Subclass) and a subclass of salaried female workers (the Salaried Subclass). Before us now are both (1) the district court's sum m ary judgm ent on the Hourly Subclass's disparate-im pact claim relating to overtim e assignm ents, certified by the district court as a final judgm ent under Fed. R. Civ. P. 54(b); and (2) several of the district court's classcertification decisions relating to both the Hourly and Salaried Subclasses, on which we provisionally granted interlocutory appeal under Fed. R. Civ. P. 23(f). Boeing has cross-appealed to challenge the district court's class certification of the Hourly Subclass's disparate-im pact claim in the event that we reverse the district court's grant of sum m ary judgm ent on that claim . W e affirm the district court's sum m ary judgm ent because Plaintiffs' statistical evidence is not adequately based on data restricted to persons eligible for overtime assignments. This affirmance moots the cross-appeal. Also, we dism iss Plaintiffs' appeal of the district court's class-action decisions because they were not filed within 10 days of the district court's initial decision denying class certification. Finally, we reject the claim s of three former class representatives who were stripped of that designation by the district court on the ground that they could not "fairly and adequately protect the interests of the class," Fed. R. Civ. P. 23(a)(4). -3-

I.

BACKGROUND Title VII of the Civil Rights Act of 1964 prohibits, am ong other things,

discrim ination on the basis of sex. See 42 U.S.C. § 2000e-2(a). Two types of claim s are recognized under Title VII: disparate treatment and disparate im pact. "Disparate treatm ent" . . . is the most easily understood type of discrim ination. The em ployer sim ply treats some people less favorably than others because of their race, color, religion, sex, or national origin. Proof of discrim inatory m otive is critical, although it can in som e situations be inferred from the mere fact of differences in treatm ent. . . . Claim s of disparate treatm ent m ay be distinguished from claim s that stress "disparate im pact." The latter involve employm ent practices that are facially neutral in their treatm ent of different groups but that in fact fall m ore harshly on one group than another and cannot be justified by business necessity. Proof of discrim inatory m otive . . . is not required under a disparate-im pact theory. Either theory m ay, of course, be applied to a particular set of facts. Int'l Bhd. of Teamsters v. United States, 431 U.S. 324, 335 n.15 (1977) (citations om itted). In a disparate-im pact claim the plaintiff is challenging an employm ent practice that is "`fair in form , but discrim inatory in operation.'" Bullington v. United Air Lines, Inc., 186 F.3d 1301, 1312 (10th Cir. 1999) (quoting Griggs v. Duke Power Co., 401 U.S. 424, 431 (1971), overruled on other grounds by Nat'l R.R. Passenger Corp. v. M organ, 536 U.S. 101 (2002). "[A] plaintiff m ay establish a prim a facie case of disparate im pact discrim ination by showing that a specific identifiable em ploym ent practice or policy caused a significant disparate im pact on a protected group." Id. (internal quotation m arks om itted). This

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burden, which had been im posed by caselaw, see, e.g., Ortega v. Safeway Stores, Inc., 943 F.2d 1230, 1242 (10th Cir. 1991), was codified by statute in 1991. See 42 U.S.C. § 2000e-2(k); Civil Rights Act of 1991, Pub. L. No. 102-166, § 105(a), 105 Stat. 1071, 1074-75. The 1991 statute departed from case law in several respects, but none are relevant here. Discrim ination suits are often filed as putative class actions. W hether a suit can proceed as a class action is governed by Fed. R. Civ. P. 23. Under that rule the district court m ust determ ine "at an early practicable tim e," Fed. R. Civ. P. 23(c)(1)(A), whether a suit (or a particular claim within a suit) satisfies the prerequisites of num erosity, comm onality, typicality, and adequacy of representation, see id. 23(a), and falls within one of the categories of actions m aintainable as class actions, see id. 23(b). W e review de novo whether the district court applied the correct legal standard in its decision to grant or deny class certification; when the district court has applied the proper standard, the decision will be reversed only for abuse of discretion. See Shook v. El Paso County, 386 F.3d 963, 967-68 (10th Cir. 2004). The district court can modify or am end its class-certification determ ination at any time before final judgm ent in response to changing circum stances in the case. See Fed. R. Civ. P. 23(c)(1)(C). In 2000, Plaintiffs, among others, filed a putative nation-wide class-action suit in the United States District Court for the W estern District of W ashington, alleging gender discrim ination in a variety of Boeing's com pensation practices. -5-

The district court, however, certified only a class of female employees working at Boeing's W ashington facilities. In 2002 non-W ashington plaintiffs filed suits in several states, including this suit in the District of Kansas. Boeing's W ichita facility includes operations of three m ajor business units: Boeing Com m ercial A irplanes, which is the largest group at the facility and is responsible for comm ercial production; the W ichita Developm ent and M odification Center, which is responsible for the site's m ilitary business; and the Shared Services G roup, which provides infrastructure support. According to the com plaint, the W ichita facility is Boeing's largest m anufacturing business. In Decem ber 2001 Boeing had approximately 16,700 em ployees in K ansas. This appeal concerns Plaintiffs' Title VII claim s alleging gender discrim ination in Boeing's com pensation and overtim e policies. Nine of the Plaintiffs (the Carpenter Plaintiffs) seek to represent themselves and a class of sim ilarly situated current and form er fem ale em ployees at Boeing's W ichita facility. The other three Plaintiffs (the D ean Plaintiffs) are mem bers of the class but represent only them selves on appeal. The Hourly Subclass's overtim e claim s were brought under both disparateim pact and disparate-treatm ent theories. The claim s are based on the allegation that the discretion given to supervisors in assigning overtim e resulted in wom en receiving consistently fewer overtim e assignm ents than their m ale counterparts. In their disparate-treatm ent claim , they allege further that Boeing's failure to act -6-

upon knowledge of the denial of those assignm ents constituted intentional discrim ination against its fem ale em ployees. The Salaried Subclass m ade a disparate-impact claim that Boeing's com pany-wide practices for setting both starting salaries and raises systematically disadvantaged its female employees and a disparate-treatm ent claim that the company had failed to take action to correct the discrim inatory im pact since learning of it in 1995. Not at issue are other claim s brought by the two subclasses and the claim s of a putative subclass of female salaried engineers. II. C LA SS C ER TIFIC A T IO N There have been several class-certification proceedings before the district court in this case. The court's initial certification decision, on April 25, 2003, granted certification under Rule 23(b)(2) to both the Hourly and Salaried Subclasses on their disparate-impact claims. Certification was denied on all disparate-treatm ent claim s. On February 24, 2004, following m erits discovery, the court granted Boeing's m otion to decertify the disparate-im pact claim of the Salaried Subclass, leaving the overtime disparate-impact claim of the Hourly Subclass as the only claim certified for class-action treatm ent under Rule 23. Plaintiffs filed a Renewed M otion for Class Certification (First Renewed M otion) on April 2, 2004, seeking recertification of the Salaried Subclass's disparate-im pact claim s. The court prom ptly denied the motion. Plaintiffs filed a Second Renewed M otion for Class Certification (Second Renewed M otion) on -7-

August 27, 2004, seeking certification of the disparate-treatment claims of both the Hourly and Salaried Subclasses and again asking for recertification of the Salaried Subclass's disparate-im pact claim . The district court denied the motion on Septem ber 8, 2004. Plaintiffs then filed with this court an application to appeal under Rule 23(f) the denial of their Second Renew ed M otion as it related to the claim s of the Salaried Subclass. Although Plaintiffs sought certification of the disparatetreatm ent claim of the Hourly Subclass in their Second Renewed M otion, they abandoned that issue on appeal. Despite asserting in the application that the relief sought was "leave to appeal the district court's decision denying Plaintiffs' Second Renewed M otion for Class Certification," Pet. for Perm ission to Appeal at 11, the application refers only to the claim s of the Salaried Subclass and its argum ents relate only to the certification determ inations m ade with respect to that subclass. Therefore, we will address only the claim s of the Salaried Subclass. Boeing argues that Plaintiffs' application was untim ely under Rule 23(f), and that we therefore lack jurisdiction to consider it. W e provisionally granted the application pending briefing and argum ent on our jurisdiction and the m erits of the appeal. Upon further consideration we dism iss the application as untimely and do not reach the m erits of the appeal. A. Fed. R . C iv. P. 23(f)

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Rule 23 was am ended in 1998 to add subsection (f), which perm its interlocutory appeals of district court orders granting or denying class certification. It states: A court of appeals m ay in its discretion perm it an appeal from an order of a district court granting or denying class action certification under this rule if application is made to it within ten days after entry of the order. An appeal does not stay proceedings in the district court unless the district judge or the court of appeals so orders. Fed. R. Civ. P. 23(f). Interlocutory appeals have long been disfavored in the law, and properly so. They disrupt and delay the proceedings below. See 19 James W m . M oore, M oore's Federal Practice § 201.10[1] (3d ed. 2006) ("The purposes of the final judgm ent rule are to avoid piecem eal litigation, to prom ote judicial efficiency, and to defer to the decisions of the trial court. Unfettered interlocutory appeals would disrupt both the trial and appellate processes."); 15A Charles A lan W right, Arthur R. M iller & Edward H. Cooper, Federal Practice and Procedure § 3907, at 269 (2d ed. 1991) ("W hen courts attempt to explain the policies that underlie the final judgm ent rule, . . . [they] speak of `efficiency,' protecting the role of the trial judge, and the need to avoid such evils as interference with the trial court, deciding unnecessary issues, and deliberate delay or harassm ent."). But som etim es countervailing considerations predominate. The consideration that led to adoption of subsection (f) is that a class-certification determ ination can force a resolution of the case that is independent of the merits. W hen class-action status -9-

is denied, the plaintiffs m ay need to abandon the case, or settle for a pittance, because the cost of continuing will far outweigh any potential recovery in the individual actions remaining. And when class-action status is granted, the defendant m ay be facing such enorm ous potential liability that a significant settlem ent becom es the only prudent course. As the Advisory Com m ittee note puts it: [S]everal concerns justify expansion of present opportunities to appeal. An order denying certification m ay confront the plaintiff with a situation in which the only sure path to appellate review is by proceeding to final judgm ent on the m erits of an individual claim that, standing alone, is far smaller than the costs of litigation. An order granting certification, on the other hand, m ay force a defendant to settle rather than incur the costs of defending a class action and run the risk of potentially ruinous liability. These concerns can be m et at low cost by establishing in the court of appeals a discretionary power to grant interlocutory review in cases that show appeal-worthy certification issues. Fed. R. Civ. P. 23 advisory com m ittee's note, 1998 Am endm ents, Subdivision (f). But this opportunity for an interlocutory appeal is tightly confined. First, "[t]he court of appeals is given unfettered discretion whether to permit the appeal, akin to the discretion exercised by the Supreme Court in acting on a petition for certiorari." Id. And second, there is a short time limit-- 10 days-- within which the aggrieved party can ask the court of appeals to exercise its discretion. See id. ("The 10-day period for seeking permission to appeal is designed to reduce the risk that attempted appeals w ill disrupt continuing proceedings."). Because this

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timeliness requirement is mandatory 1 , we m ust first determine w hether Plaintiffs satisfied it. B. T im eliness

The district court denied Plaintiffs' Second Renewed M otion by order entered on September 8, 2004. Plaintiffs assert that their application filed on September 22, 2004, was tim ely because it was filed within 10 days of the district court's disposition. See Fed. R. Civ. P. 6(a) (com putation of time); Beck v. Boeing Co., 320 F.3d 1021, 1022-23 (9th Cir. 2003) (Fed. R. Civ. P. 6(a) governs the tim eliness of applications under Rule 23(f)). The validity of that assertion depends on whether the district court's denial was "an order . . . granting or denying class action certification." Fed. R. Civ. P. 23(f). Boeing contends that the district court's order was sim ply a refusal to reconsider its prior rulings

W e are among several circuits that have treated the timeliness requirement as jurisdictional. See, e.g., Delta Airlines v. Butler, 383 F.3d 1143, 1144 (10th Cir. 2004) (per curiam ) ("Because the petition was not filed within the mandated time period, we dism issed for lack of jurisdiction."); M cNamara v. Felderhof, 410 F.3d 277, 280 (5th Cir. 2005) ("Unless som e exception applies, we lack appellate jurisdiction to entertain the [untim ely] petition."). The Supreme Court's recent decision in Eberhart v. United States, 126 S.Ct. 403, 406 (2005), however, casts doubt on the notion that the timeliness of notices of appeal generally is jurisdictional, see In re Special Grand Jury 89-2, 450 F.3d 1159, 1166 n.2 (10th Cir. 2006), and could have similar implications for Rule 23(f), see Coco v. Incorporated Village of Belle Terre, 448 F.3d 490, 491 (2d Cir. 2006) (per curiam). Even if it is not jurisdictional, however, it is unquestionably "mandatory" if properly raised by the opposing party, as was the case here. Because we must dismiss the appeal in either event, we need not analyze Eberhart's impact on Rule 23(f). -11-

1

denying certification to the Salaried Subclass and not itself an order appealable under Rule 23(f). W e agree with Boeing. In a sense, an order denying a m otion to reconsider a decision on class certification is an "order . . . granting or denying class action certification." But that cannot be the sense in which the term is used in Rule 23(f), because that construction of the term would underm ine the 10-day tim e lim it for filing an application for review . One who failed to file an application in time could sim ply file a m otion to reconsider; and when that is denied, the 10-day period would restart. See Gary v. Sheahan, 188 F.3d 891, 893 (7th Cir. 1999) ("Accepting an appeal from such a decision [leaving the class definition in place] would abandon the tim e lim it for all practical purposes. That step would be both unauthorized and imprudent."); cf. M cNamara, 410 F.3d at 281 ("[T]o hold that-- no m atter how styled-- a motion under Rule 23(c) [to alter or amend a class-certification decision] is always distinct from a m otion to reconsider w ould allow a party to subvert the ten-day tim e lim it prescribed in Rule 23(f)."). One might argue, as Plaintiffs do, that this reasoning does not apply when the m otion for reconsideration raises new argum ents, based on new developm ents in the case. But the need to avoid causing delay and disruption to the district court proceedings cautions against an appellate court's engaging in detailed inspection and analysis of the record to determ ine how new an argum ent is and whether the underlying evidence was reasonably available when certification was -12-

originally litigated. M oreover, there can be little doubt that review of an order denying a motion for reconsideration would have to be lim ited to the new elements in the motion-- the original order regarding certification m ust be presum ed correct, or there would be a clear end run around the 10-day lim it. Yet given the multifactor analysis that courts m ust apply in deciding the propriety of class certification, such a lim ited review would often require contorted thinking that exceeds the capacities of even appellate courts. How can an appellate court say that one particular new factor would require a different result regardless of how the district court weighed the factors presented originally? In stating that the new factor required a different result, the appellate court m ust engage in weighing the factors weighed by the district court in its original ruling but cannot know precisely how much weight the district court granted to each. In particular, what if the district court clearly erred in giving dispositive weight to one factor? How is the appellate court to ignore such error (in keeping with the presum ption that the original decision was correct) even when it addresses a motion for reconsideration that raises only a rather inconsequential new factor? To be sure, we do review m otions to reconsider in certain circumstances, such as denials of m otions under Fed. R. Civ. P. 60(b). But the predicate for that review-- for exam ple, fraud or newly discovered evidence-- is largely collateral to the m erits of the decision. W e are not inclined to adopt a construction of Rule 23(f) that would regularly require m ental gym nastics just for the purpose of giving litigants -13-

a second bite at the interlocutory-appellate-review apple. W e note that the very absence of a prom pt appeal by the party aggrieved by the decision on certification suggests that the concerns justifying Rule 23(f) are, at the least, less significant in the particular case. If the decision whether or not to certify the class w as truly outcome determ inative, one would not expect the losing party to continue the litigation for m onths before launching a new challenge to the ruling. Any value in perm itting a belated interlocutory appeal is overridden by the desirability of the district court's proceeding expeditiously. W e recognize that Rule 23(c)(1)(C) perm its the district court to alter or amend a certification decision. And parties m ay suggest such changes as the factual record and legal theories develop. All we are saying is that there can be no Rule 23(f) appeal from the denial of such a suggestion. An order that leaves class-action status unchanged from what was determ ined by a prior order is not an order "granting or denying class action certification." Of course, when the district court accepts a suggestion and the certification decision is changed, the new order, to the extent it m odifies the prior order, is indeed such an order and an interlocutory appeal under Rule 23(f) is perm itted. See G ary, 188 F.3d at 893 ("[I]f in response to a belated m otion for reconsideration the judge m aterially alters the decision, then the party aggrieved by the alteration m ay appeal within the normal time.").

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In addition, we note the special case of m otions to reconsider filed within 10 days of the district court's certification decision. The Supreme Court has long recognized that m otions to reconsider toll the tim e for appeal when they are filed within the tim e for filing a notice of appeal. See United States v. Dieter, 429 U.S. 6, 8 & n.3 (1976) ("[T]he consistent practice in civil and crim inal cases alike has been to treat tim ely petitions for rehearing as rendering the original judgm ent nonfinal for purposes of appeal for as long as the petition is pending."). This recognition stems from the clear advantage of providing the district court an opportunity to correct its own error, as long as doing so does not underm ine the time limit for pursuing an appeal. W e assum e, without having to decide in this case, that such m otions to reconsider w ould also toll the tim e lim it in Rule 23(f). See, e.g., M cNam ara, 410 F.3d at 281 (recognizing the tolling effect of a timely m otion to reconsider in the R ule 23(f) context). The district court first denied certification of the Salaried Subclass's disparate-treatm ent claim on April 25, 2003. Plaintiffs did not exercise their right to file a Rule 23(f) petition within 10 days of that order. The district court's determ ination as to that claim has not changed in all the subsequent proceedings, so there has not been any other order "granting or denying class action certification" that would trigger another period for seeking interlocutory appeal. As for class certification of the Salaried Subclass's disparate-im pact claim , the district court initially certified the class in its April 25, 2003, order, which Boeing -15-

did not appeal. On February 24, 2004, however, it granted Boeing's m otion to decertify. At that juncture Plaintiffs could have sought our review under Rule 23(f), but they did not do so. Despite two attem pts to have the district court recertify that claim , in both Plaintiffs' First Renewed M otion and their Second Renewed M otion, the district court's ruling on certification has not changed again. Therefore, neither of the orders denying those motions was an order granting or denying certification and neither triggered a new period for filing a Rule 23(f) application. Plaintiffs' Rule 23(f) application on September 22, 2004, m ust be dism issed as an untim ely attempt to have us review the court's orders of April 25, 2003, and February 24, 2004. Any appeal of those certification decisions m ust await final judgm ent. See G ary, 188 F.3d at 892. III. SU M M A R Y JU D G M E N T On February 24, 2004, the district court granted Boeing's m otion for sum m ary judgment on the disparate-impact claim of the Hourly Subclass. On August 11, 2004, the court certified that ruling as a final judgm ent, see Fed. R. Civ. P. 54(b), and Plaintiffs filed a tim ely appeal. Boeing filed a cross-appeal seeking decertification of this subclass should we reverse the sum m ary-judgm ent ruling. B ecause w e affirm the district court's grant of summary judgment, we need not address the cross-appeal. A. Standard of R eview

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Our standard of review on sum m ary judgm ent is de novo; we apply the sam e legal standard to be used by the district court. Garrison v. Gambro, Inc., 428 F.3d 933, 935 (10th Cir. 2005). Sum m ary judgm ent should be granted if "the pleadings, depositions, answers to interrogatories, and admissions on file, together with the affidavits, if any, show that there is no genuine issue as to any m aterial fact and that the moving party is entitled to a judgm ent as a matter of law." Fed. R. Civ. P. 56(c). Neither "mere assertions and conjecture," York v. AT& T Co., 95 F.3d 948, 955 (10th Cir. 1996), nor "the existence of a scintilla of evidence in support of the nonmovant's position," Lawmaster v. W ard, 125 F.3d 1341, 1347 (10th Cir. 1997), is sufficient to show a genuine issue of m aterial fact; "an issue of m aterial fact is genuine only if the nonmovant presents facts such that a reasonable jury could find in favor of the nonm ovant," id. B. Plaintiffs' C laim

Plaintiffs com plain that wom en have been the victim s of discrim ination in the assignm ent of overtim e at Boeing's W ichita facility, being offered and receiving less than their proportionate share. They have raised both disparatetreatment and disparate-im pact claims relating to overtim e. The sum m ary judgm ent disposed of only their disparate-im pact claim . "An unlawful employm ent practice based on disparate im pact is established . . . only if . . . a com plaining party dem onstrates that a respondent uses a particular em ploym ent practice that causes a disparate im pact on the basis of . . . -17-

sex . . . ." 42 U.S.C. § 2000e-2(k)(1)(A)(i). The first step in raising a disparateim pact claim is to identify the specific employm ent practice allegedly causing the discrim inatory im pact. See W ards Cove Packing Co. v. Atonio, 490 U.S. 642, 657 (1989) ("[A] plaintiff m ust demonstrate that it is the application of a specific or particular employm ent practice that has created the disparate im pact under attack."); M aldonado v. City of Altus, 433 F.3d 1294, 1304 (10th Cir. 2006). The specific practice identified by Plaintiffs is that "B oeing supplies no guidance to m anagers on how to choose among eligible employees, and there are no centralized rules for how to choose am ong equally eligible m ale and fem ale employees." R. Doc. 340 at 23 (Plaintiffs' M em. in Opp'n to Boeing's M ot. for Sum m . J.); see also Aplt. Br. at 26. (In the sum m ary-judgm ent proceedings below, and on appeal, Plaintiffs have also claim ed discrim inatory im pact from Boeing's failure to m onitor m anagers or hold them accountable for the gender im pacts of their overtim e decisions. That allegation was not addressed by the district court. Plaintiffs' appellate briefs, however, contain no further elaboration of this claim , so we will not specifically address it. See Gross v. Burggraf Constr. Co., 53 F.3d 1531, 1546-47 (10th Cir. 1995) ("[I]t is insufficient merely to state in one's brief that one is appealing an adverse ruling below without advancing reasoned argum ent as to the grounds for appeal." (internal brackets and quotation m arks om itted)). In any event, our discussion of their claim that

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supervisors w ere given inadequate guidance in overtime assignm ents w ould likely also be dispositive of this claim .) "U nder the disparate im pact theory, a plaintiff m ust first m ake out a prim a facie case of discrim ination by showing that a specific identifiable employm ent practice or policy caused a significant disparate im pact on a protected group." M urphy v. Derwinski, 990 F.2d 540, 544 (10th Cir. 1993) (internal quotation m arks om itted). In other words, a plaintiff must "show that there is a legally significant disparity between (a) the [gender] composition, caused by the challenged em ploym ent practice, of the pool of those enjoying a job or job benefit; and (b) the [gender] com position of the qualified applicant pool . . . [, i.e.,] the pool from which potential qualified applicants m ight come." Crum v. Alabama (In re Em ployment Discrimination Litig. Against Ala., 198 F.3d 1305, 1312 & n.11 (11th Cir. 1999). The court compares the gender composition of those who are subject to the challenged em ploym ent practice with the gender com position of those enjoying the benefit for w hich the practice selects. In assessing whether a plaintiff has established a prim a facie case, it is, of course, irrelevant what happens to those who do not qualify for consideration. See Wards Cove, 490 U.S. at 650-51 ("The proper comparison is between the racial composition of the at-issue jobs and the racial composition of the qualified population in the relevant labor m arket." (emphasis added; internal quotation m arks, brackets, and ellipsis om itted)). -19-

Plaintiffs' claim rests on the assertion that supervisors are exercising their discretion (intentionally or subconsciously) to award m ales a disproportionate share of available overtim e assignm ents. To establish a prim a facie case, it is not enough for Plaintiffs to show sim ply that m ore overtim e assignm ents go to m en than to wom en, or even that men get a higher percentage of those assignm ents than their percentage in the work force. They must compare qualified m en to qualified wom en. That is, they m ust show that am ong m en and wom en who are eligible for overtim e assignm ents, a disproportionate share of overtim e assignm ents go to m en. The qualifications for overtim e assignm ent are established in the collective bargaining agreement (CBA) between Boeing and the International Association of M achinists and A erospace W orkers AFL-CIO. The CBA provides: 6.10(b) O vertim e Scheduling P rocedures for Extended W orkday or W orkw eek. (1) The norm al practice for the advance scheduling of overtim e within the shop and shift will be to: (a) First, ask the employee regularly assigned to either the m achine, job, crew, or position providing the em ployee is in attendance when the overtim e is being assigned . . . . (b) Then, ask other qualified employees in the same job classification who are in attendance when the overtim e is being assigned. (c) If sufficient volunteers are not obtained, the Com pany may designate any em ployee to satisfy remaining requirem ents. (2) M anagem ent m ay exclude an em ployee from overtim e, even if the em ployee is in attendance when the overtim e is being assigned, if: (a) The em ployee has been absent during the week . . . .

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(b) An employee is asked to work overtim e (Saturday and/or Sunday) and is subsequently absent due to illness or bereavem ent leave on the workday preceding the overtim e day. (c) Two (2) consecutive weekends have been worked by the employee. (d) One hundred forty-four (144) overtim e hours have been worked in the budget quarter. (e) Eight (8) overtim e hours have been worked on the Saturday or the Sunday. (f) A n em ployee's schedule perform ance or work quality is currently docum ented as being deficient. Rep. Aplts. Supp. App. Vol. 1 at 10-11. (This provision is from the September 2, 1999, CBA. The 1995 CBA m ay be applicable to a portion of the class period, which runs from April 2, 1999. Plaintiffs acknowledge, however, that the overtim e provisions did not change m aterially during the class period.) Plaintiffs do not dispute that the CBA applies to the challenged overtim e assignm ents. Their claim is that the discretion exercised by managers in "choos[ing] among employees who worked in the area where overtim e was required and wanted the extra pay" has created a disparity betw een sim ilarly situated m en and wom en. A plt. Br. at 26. Boeing for its part does not dispute that supervisors have som e m easure of discretion within the term s of the CBA. It argues, however, that Plaintiffs have failed to m ake a sufficient showing that this discretion has been exercised in a manner adverse to wom en. On appeal Plaintiffs contend that their statistical evidence of disparate impact suffices to preclude sum m ary judgm ent. (In district court Plaintiffs also presented a variety of anecdotal evidence to support this claim . But because on -21-

appeal they do not rely on that evidence in challenging summary judgment, we will consider only the statistical evidence.) They rely on a study by their expert, Dr. Bernard Siskin. Dr. Siskin perform ed a regression analysis that compared the overtime worked by m ale and fem ale em ployees w hom he defined as "sim ilarly situated." R. Doc. 346 (Decl. of Bernard P. Siskin, Ph.D. in O pp'n to Boeing's M ot. for Sum m . J. (hereinafter "Siskin Study")) at 22. The Siskin Study exam ined overtime assignm ents from April 2, 1999 (the beginning of the liability period for this claim ) through June 20, 2002, using Boeing's electronic daily payroll records. For weekday overtime the Siskin Study defined sim ilarly situated employees as those who "[w]orked that day and are in the same job, grade, budget code and shift." Id. at 23. Similarly situated em ployees w ith respect to weekend overtim e w ere defined as those w ho "[w ]orked Friday and are in the same job, grade, budget code and shift." Id. For each cohort of sim ilarly situated employees, the Siskin Study calculated three measures for m en and wom en: (1) the likelihood of working any overtim e; (2) the average number of overtime hours w orked; and (3) the average num ber of overtime hours paid (overtim e is paid at either 1.5 or 2 tim es a normal hour). It then computed a shortfall num ber for fem ales that described how m uch greater each m easure would be were females represented in proportion to their percentage representation in each cohort. "That is, if fem ales were 25 percent of the cohort,

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they should be 25 percent of those working overtim e and receive 25 percent of the overtim e hours and pay." Id. at 22. The Siskin Study concluded that "[h]ourly fem ale em ployees who are sim ilarly situated to m ales with respect to job, grade, shift, departm ent, and budget code are consistently and highly statistically significantly less likely to work overtime, to w ork less overtime, and to receive less overtime pay. This pattern is consistent across tim e." Id. at 3. It observed that "[c]learly, som ething in the overtim e process consistently results in m ales obtaining m ore overtim e and working m ore overtim e than females." Id. at 23. There is no dispute that "som ething" causes m en to work proportionately m ore overtim e than wom en at Boeing. The district court said that the following sum m ary was uncontroverted for purposes of sum m ary judgm ent: Between April 2, 1999, and Decem ber 31, 2001, disparities in overtim e adverse to w om en ranged between a low of 17.06 standard deviations and a high of 38.03 standard deviations. For the last period for which Dr. Siskin has analyzed data, ending June 20, 2002, the disparities w ere 10.23 standard deviations for w eekday overtim e and 7.95 standard deviations for weekend overtim e. Rep. Aplts. App. Vol.1 at 280. Boeing concedes that these differences are statistically highly significant. The Supreme Court has recognized that a disparity of m ore than two or three standard deviations in a large sample makes "suspect" the contention that the differential occurs random ly. See Hazelwood Sch. Dist. v. United States, 433

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U.S. 299, 308 n.14 (1977); Castaneda v. Partida, 430 U.S. 482, 496 n.17 (1977). Several circuit courts have adopted a similar level of significance in Title VII cases. See, e.g., Smith v. Xerox Corp., 196 F.3d 358, 366 (2d Cir. 1999); Brown v. Philip M orris Inc., 250 F.3d 789, 809 (3d Cir. 2001); Lewis v. Bloomsburg M ills, Inc., 773 F.2d 561, 568-69 (4th Cir. 1985) (five to eight standard deviations); Adams v. Ameritech Servs., Inc., 231 F.3d 414, 424 (7th Cir. 2000). But despite recognizing that the statistics show that m en have worked proportionately m ore overtim e than wom en, Boeing claim s that the Siskin Study nonetheless fails to establish a prim a facie case. It contends that the Siskin Study does not show that the "som ething" causing m en to work m ore overtim e than wom en is the manager discretion that Plaintiffs have identified as the challenged em ploym ent practice. Boeing's argum ent appears to be that the "som ething" is a variable other than those that the Siskin Study included in the statistical m odel-- nam ely, job, grade, budget code, and shift. According to Boeing, other variables affecting overtim e assignm ents-- such as the CBA criteria and potential differences in the rates at which men and wom en volunteer for overtim e-- are not controlled for in the Siskin Study and could be responsible for the observed disparities. The district court agreed with Boeing that a statistical study could not establish a claim without considering such variables and granted Boeing's m otion for sum m ary judgm ent on that basis. Before addressing Boeing's argum ents, with

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which we agree in part, we review the legal framework for the use of statistical evidence in Title VII cases. C. Statistical E vidence - G eneral Principles

Statistical evidence is an acceptable, and comm on, m eans of proving disparate im pact. See, e.g., Sandoval v. City of Boulder, 388 F.3d 1312, 1326 (10th Cir. 2004); Bullington, 186 F.3d at 1312 ("As is typical in disparate im pact cases, [plaintiff] relies on statistical evidence to establish her prim a facie case."); M ountain Side Mobile Estates P'ship v. Sec'y of HUD, 56 F.3d 1243, 1251 (10th Cir. 1995) ("In Title VII em ploym ent discrim ination cases, plaintiffs m ay rely solely on a statistical showing of disparate effect to establish a prim a facie case of disparate im pact."). The statistics m ust, however, relate to the proper population. For example, when the claim is disparate im pact in hiring, the statistics should be based on data with respect to persons qualified for the job. See W ards Cove, 490 U.S. at 650-51 ("It is such a com parison-- between the racial composition of the qualified persons in the labor m arket and the persons holding at-issue jobs-- that generally form s the proper basis for the initial inquiry in a disparate-im pact case."); see also Bullington, 186 F.3d at 1314 ("[Plaintiff's] applicant pool was appropriately limited to persons w ho sought out and were at least m inimally qualified for the position . . . ."). The same requirement applies to other job benefits. See Crum, 198 F.3d at 1309, 1312 (relating to alleged discrim ination in "layoffs, recalls from layoffs, term inations, discipline, hiring, rehiring, -25-

evaluations, com pensation, transfers, job duty assignm ents, recruitment, screening, selection procedures, denial of prom otions, demotions, rollbacks, sick leave, subjective decision-m aking practices, and other term s and conditions of em ploym ent" (internal quotation m arks om itted)). The essential requirem ent is that the data concern those persons subject to the challenged em ploym ent practice. After specifying the employm ent practice allegedly responsible for excluding m em bers of their protected class from a benefit, plaintiffs m ust identify the correct population for analysis. In the typical disparate im pact case the proper population for analysis is the applicant pool or the eligible labor pool. The com position of this population is com pared to the com position of the em ployer's workforce in a relevant m anner, depending on the nature of the benefit sought. Smith, 196 F.3d at 368. W hen the selection process is only partially subjective, a disparate-im pact plaintiff should control for the constraints placed upon the decisionm aker's discretion. See Anderson v. W estinghouse Savannah River Co., 406 F.3d 248, 266-67 (4th Cir. 2005); cf. W atson v. Fort W orth Bank & Trust, 487 U.S. 977, 994 (1988) (O'Connor, J., plurality opinion) ("Especially in cases where an em ployer com bines subjective criteria w ith the use of m ore rigid standardized rules or tests, the plaintiff is in our view responsible for isolating and identifying the specific em ploym ent practices that are allegedly responsible for any observed statistical disparities.").

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To be sure, the population selected for statistical analysis need not perfectly m atch the pool of qualified persons. Such perfection m ay be impossible to obtain. W hen reliable data regarding that pool are unavailable, a different population m ay be used if it adequately reflects the population of qualified persons. See Ramona L. Paetzold & Steven L. W illborn, The Statistics of Discrim ination § 5.04 (2002) ("In som e instances, where applicant data are not available, reliable, or are believed to be biased, and where statistical inform ation regarding the labor m arket is difficult to ascertain, the general population m ight adequately reflect the population of qualified job applicants."); see also M alave v. Potter, 320 F.3d 321, 326-27 (2d Cir. 2003) ("[I]t was error [to reject] out of hand [Plaintiff's] statistical analysis sim ply because it failed to conform to the preferred m ethodology described in W ards Cove, given the Suprem e Court's express endorsement in that decision of alternative methodologies if the preferred statistics are `difficult' or `im possible' to obtain."); cf. Trout v. Lehman, 702 F.2d 1094, 1102 (D.C. Cir. 1983) (in disparate-treatment case brought before the Civil Rights A ct of 1991, "plaintiffs cannot legitim ately be faulted for gaps in their statistical analysis when the inform ation necessary to close those gaps was possessed only by defendants and was not furnished either to plaintiffs or to the Court" (internal quotation m arks om itted)), vacated on other grounds by Lehman v. Trout, 465 U.S. 1056 (1984), and abrogated on other grounds by Berger v. Iron W orkers Reinforced Rodmen, Local 201, 170 F.3d 1111, 1124-25 (D.C. Cir. -27-

1999). For example, in Dothard v. Rawlinson, 433 U .S. 321 (1977), the Suprem e Court determ ined that plaintiffs who were challenging Alabama's height and weight requirements for prison guards could use height and weight statistics based on national data for com parison. "[R ]eliance on general population dem ographic data was not m isplaced where there was no reason to suppose that physical height and weight characteristics of Alabama men and wom en differ m arkedly from those of the national population." Id. at 330. Nevertheless, absent a close fit between the population used to m easure disparate im pact and the population of those qualified for a benefit, the statistical results cannot be persuasive. "[S]tatistics based on an applicant pool containing individuals lacking m inim al qualifications for the job would be of little probative value." W atson, 487 U.S. at 997. Thus, a statistical analysis cannot establish a plaintiff's prim a facie case unless it is based on data restricted to qualified em ployees, or (1) reliable data with respect to that group are unavailable and (2) the plaintiff establishes that the statistical analysis uses a reliable proxy for qualification. This approach holds plaintiffs to their statutory burden to "dem onstrate[] that a respondent uses a particular em ploym ent practice that causes a disparate im pact on the basis of . . .

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sex," 42 U.S.C. § 2000e-2(k)(1)(A )(i), without imposing an insurm ountable burden when reliable data on a qualification are not available. 2 D. A pplication to this C ase

The employm ent practice challenged by Plaintiffs is the exercise of discretion by supervisors in assigning overtim e. As stated in Smith, "[T]he proper

The statute provides another avenue for plaintiffs when the particular aspect of the process that is claimed to be objectionable cannot be isolated: [T]he complaining party shall demonstrate that each particular challenged employment practice causes a disparate impact, except that if the complaining party can demonstrate to the court that the elements of a respondent's decisionmaking process are not capable of separation for analysis, the decisionmaking process may be analyzed as one employment practice. 42 U.S.C. § 2000e-2(k)(1)(B)(i). Plaintiffs argue in their reply brief to this court that they "presented facts below that defendant's collective bargaining agreements imposed no meaningful objective standards on supervisors in assigning overtime" and that "[s]uch a showing is sufficient to trigger subsection 2000e2(k)(1)(B)(i)." Rep. Aplts. Reply Br. at 10. But they provide no citation to the record showing that they raised this issue in district court, and we cannot find in the record anything indicating to that court that they were attempting to make the required showing of analytical inseparability. W e will not address the potential application of § 2000e-2(k)(1)(B)(i) to Plaintiffs' claim, because our general rule is not to address arguments that were not first presented to the district court, see Cummings v. Norton, 393 F.3d 1186, 1190 (10th Cir. 2005) (the "general rule that issues not raised below are waived on appeal" is particularly important on appeal of summary judgment); Bancamerica Commercial Corp. v. M osher Steel of Kansas, Inc., 100 F.3d 792, 798-99 (10th Cir. 1996) ("W here a litigant changes to a new theory on appeal that falls under the same general category as an argument presented at trial or presents a theory that was discussed in a vague and ambiguous way the theory will not be considered on appeal." (brackets and internal quotation marks omitted)), and we particularly frown on the making of new arguments in a party's reply brief, see Stump v. Gates, 211 F.3d 527, 533 (10th Cir. 2000). -29-

2

population for analysis is the . . . eligible labor pool." 196 F.3d at 368. The Boeing hourly employees eligible for an overtim e assignm ent are those who satisfy the CBA requirements for the assignm ent; that is, the challenged practice operates only w ith respect to employees eligible under the CBA. The CBA requires that overtime first be offered to "the em ployee regularly assigned to either the machine, job, crew, or position" for which overtim e is to be scheduled, and then to others within the sam e "shop or shift." Rep. Aplts. Supp. App. Vol. 1 at 10. The Siskin Study, however, did not incorporate the CBA's eligibility requirements in its analysis. Instead, it controlled for "job," "grade," "budget code," and "shift." R. Doc. 346 at 23. The implicit assum ption is that two hourly workers with the same job, grade, budget code, and shift have equal opportunities for overtim e assignm ents under the CBA, subject to the supervisor's discretion. There is certainly overlap between the Siskin Study variables and those used to determ ine overtim e assignm ents. But the tw o sets of variables are not the sam e. Am ong the qualifications included in the CBA, the Siskin Study controlled for only "job" and "shift." It did not account for whether wom en worked on the "machine" or were in the "crew," "position," or "shop" to which the overtim e was assigned. This failure can skew the results. If, for exam ple, overtim e assignm ents were concentrated in a handful of shops and alm ost no wom en worked in those shops, a discrepancy found in the Siskin Study between the overtime worked by m en and by wom en would not at all represent a disparate -30-

impact created by the supervisor's discretionary choice am ong eligible employees. Rather, it could sim ply be a reflection of the gender distribution among those eligible for overtim e. At the outset, therefore, it appears that the Siskin Study cannot establish a prim a facie case based on a com parison "between (a) the [gender] composition, caused by the challenged em ploym ent practice, of the pool of those enjoying a . . . job benefit; and (b) the [gender] composition of the qualified applicant pool," Crum, 198 F.3d at 1312, because the study is not lim ited to data regarding those qualified people subject to the challenged practice. The study does not isolate the effect of supervisor discretion from the effect of the CBA requirem ents. See Anderson, 406 F.3d at 260. Accordingly, we look to whether Plaintiffs have adequately established that (1) reliable data on the omitted CBA criteria were unavailable and (2) they used a reliable proxy. They have not. To begin with, Plaintiffs have not established that the data necessary to establish the im pact on CBA-qualified workers were unavailable. Plaintiffs acknowledge that variables such as crew, position, and shop are relevant to qualification for overtim e under the CBA but claim that they cannot be held responsible for including them in their statistical analysis because "Boeing did not m aintain electronic data on any of the omitted variables." Rep. Aplts. Br. at 35. But data m ay be available in nonelectronic form . Electronic data are undeniably m ore convenient, especially for use in statistical studies, but inconvenience does not excuse failure to collect the data. Plaintiffs have -31-

presented no reason why the omitted inform ation could not have been procured through other m ethods, such as depositions or interrogatories. It appears that they were sim ply satisfied with Boeing's indication that the data w ere unavailable in their electronic payroll records. Furtherm ore, even were we convinced that the data are unavailable, Plaintiffs have failed to dem onstrate that the variables in the Siskin Study's statistical analysis produce a reliable surrogate for qualifications for overtim e; that is, that the results accurately reflect comparisons between individuals who were equally eligible for overtim e assignm ents under the CBA. Plaintiffs m ake the bald claim that the "grade" and "budget code" variables used by the Siskin Study are equivalent to the omitted variables "crew," "position," and "shop." See Rep. Aplts. Reply Br. at 5 ("[I]n the absence of specific electronic data m aintained by Boeing identifying employees' `shops' or `crews,' [Dr. Siskin] closely tracked this inform ation by using as a proxy budget codes and grade levels that reflected their area and level of w ork."). But they m ake no attem pt to explain the basis of this claim . W e cannot agree that those relationships are as self-evident as Plaintiffs apparently believe them to be. The record does not even indicate what a "budget code" is. Plaintiffs' "m ere assertion" will not suffice. See York, 95 F.3d at 955. Accordingly, we agree with the district court that the Siskin Study was insufficient to establish a prim a facie disparate-im pact case.

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Plaintiffs rely on Bazemore v. Friday, 478 U.S. 385, 400 (1986), and Bullington, 186 F.3d at 1314, to argue that failure to define perfectly the population of qualified employees does not prevent the Siskin Study from establishing their claim . Both decisions are distinguishable, however, because the m issing variables considered by the two courts did not relate to m inimal, objective qualifications. A jury could decide that the m issing variable in those cases w as not likely to affect the exercise of discretion to a significant extent-- a rather different matter from ignoring a factor that disqualifies a candidate before discretion comes into play. In Bazemore the United States and others brought a pattern-or-practice suit against the North Carolina Agricultural Extension Service, alleging racial discrim ination in salaries; the plaintiffs offered statistical evidence that controlled for race, education, tenure, and job title. See 478 U.S. at 398. The court of appeals had upheld the district court's rejection of the statistical evidence, ruling that "`the regression analysis presented here must be considered unacceptable as evidence of discrim ination,'" because it "`om itted . . . variables which ought to be reasonably viewed as determ inants of salary,'" id. at 399-400 (quoting Bazemore v. Friday, 751 F.2d 662, 672 (4th Cir. 1984)), particularly geographic variations in salary, Bazemore, 478 U.S. at 399. The Supreme Court disagreed. Introducing its analysis it noted that "if the defendants have not succeeded in having a case dism issed on the ground that plaintiffs have failed to establish a prim a facie case, -33-

and have responded to the plaintiffs' proof by offering evidence of their own, the factfinder then must decide whether the plaintiffs have dem onstrated a pattern or practice of discrim ination by a preponderance of the evidence." Id. at 398. It then said, "[I]t is clear that a regression analysis that includes less than `all m easurable variables' m ay serve to prove a plaintiff's case . . . . W hether, in fact, such a regression analysis does carry the plaintiff's ultim ate burden will depend in a given case on the factual context of each case in light of all the evidence presented by both the plaintiff and the defendant." Id. at 400 (internal citation om itted). The Court remanded for consideration of the particular characteristics of the regression analysis to determ ine whether it was sufficiently probative. A s we understand the opinion, the regression analysis was not used to establish the prim a facie case, but to prove discrim ination once the presence of a prim a facie case was established, or at least uncontested. The prim a face case required a showing that qualified blacks were receiving lower salaries than qualified whites. The regression analysis then exam ined whether other factors-- such as education, tenure, and job title-- could account for this difference. Failure to take into account all potential factors did not necessarily render the regression analysis unprobative. M oreover, there was no question in Bazem ore, as there is here, regarding whether the data concerned persons who were not qualified or eligible for the benefit at issue-- namely, a higher salary. The statistical study compared salaries -34-

of persons employed by the extension service. The issue was whether discretion in setting salaries was exercised in a discrim inatory m anner. The statistical study took into account som e factors that m ight influence the exercise of discretion and om itted others; but there is no indication that it om itted any factor that was a nondiscretionary determ inant of salary (such as a maxim um salary established for a specific job title). Bullington considered a disparate-impact claim of gender discrim ination in the hiring of airline flight officers. See 186 F.3d at 1312. The plaintiff offered statistics indicating that the interview pass rate for wom en was only 60% of the pass rate for m en. See id. The district court rejected the statistical study and granted sum m ary judgm ent to the airline, because the pass rates were not adjusted for hypothesized differences in aeronautical experience betw een m en and wom en. Id. at 1312-13. W e reversed, concluding that the statistics were "sufficiently reliable" because the study was properly lim ited to individuals who were m inim ally qualified for the positions (otherwise they would not have been given an interview in the first place). Id. at 1314. Again, the statistical study examined only the exercise of discretion-- this tim e in the interview process. A jury can weigh whether om ission of a factor that could affect the exercise of discretion renders an analysis unpersuasive. But no one could disagree that an objective eligibility requirem ent is a necessary com ponent of the analysis.

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Thus, the variables om itted from the regression analyses in both Bazemore and Bullington related to characteristics that did not affect whether the population studied was "m inimally qualified" for the benefit sought. The geographic variations in salary at issue in Bazem ore had nothing to do with whether a particular individual was m inim ally qualified to receive a higher salary. See 478 U.S. at 398. In Bullington the level of aeronautical experience was certainly a perm issible consideration in the interview process, but it was only one of m any factors considered in a subjective determ ination, not a mandatory criterion for being hired. In contrast, the Siskin Study did not confine itself to the persons eligible for an overtim e assignm ent. See Ortega, 943 F.2d at 1245 (statistics not probative because they did not take into account qualifications for the jobs available). Our conclusion is not undermined by the "m assive overtim e disparities" that Plaintiffs allege are revealed by the Siskin Study's analysis. Rep. Aplts. Br. at 38. They contend that these disparities are so large that a substantial disparity would certainly be present even if the statistical analysis were adjusted to account for the CBA requirements. Plaintiffs argue: Boeing's expert report affirm atively demonstrated that the gender of the employee regularly assigned to the machine or position for which overtim e w ork w as needed w as largely irrelevant to the overtim e disparities. Boeing's expert determ ined that, for 78% of overtim e opportunities, m ore than one em ployee was eligible to work the overtim e. Thus, even if there had been reason to believe that more m en than wom en were the sole employees regularly assigned to the -36-

m achine or position for which overtim e work was required, less than 25% of the overtim e opportunities studied by Siskin would have been affected by his om ission of this variable. Viewed in the light m ost favorable to plaintiffs, this fact casts grave doubt on whether the om ission of this variable explains the massive overtim e disparities found by Siskin, precluding the district court from rejecting Siskin's analysis on this ground. Id. at 37-38 (record citation om itted). As we now proceed to explain, however, this argum ent misapprehends the statistical evidence by confusing the magnitude of the disparities w ith their level of statistical significance, as m easured in standard deviations. There is no dispute that the Siskin Study's regression analysis reflected a difference in the amount of overtim e worked by men and wom en that was m any standard deviations removed from equality. The Siskin Study computed departures from equal treatm ent of m en and wom en whose statistical significance ranged from 7.95 standard deviations (weekend overtim e during 2002) to 38.03 (weekday overtim e during 1999). That statistical significance, however, does not necessarily m ean that the departure from equality was large. For example, the Siskin Study calculated that wom en worked an average of 19% fewer hours of weekday overtim e in 1999, 17% fewer in 2000 and 2001, and 11% fewer in 2002. For weekend overtim e it calculated that wom en worked an average of 18% fewer overtim e hours in 1999, 19% fewer in 2000, 18% fewer in 2001, and 10% fewer in 2002. Although notable, these are not what m ost would call "massive disparities"-- it is nothing like men receiving proportionately even twice as m uch -37-

overtim e as wom en. Indeed, guidelines from the Equal Em ploym ent Opportunity Com m ission draw a line (albeit not a rigid one) at a 20% disparity: A selection rate for any race, sex, or ethnic group which is less than four-fifths (4/5)(or eighty percent) of the rate for the group with the highest rate will generally be regarded by the Federal enforcement agencies as evidence of adverse impact, while a greater than fourfifths rate will generally not be regarded by Federal enforcement agencies as evidence of adverse im pact. 29 C.F.R. § 1607.4(D); accord 28 C.F.R. § 50.14(4)(D) (Departm ent of Justice Guidelines); see Smith, 196 F.3d at 365 (treating "four-fifths" guideline as persuasive); Thom as v. M etroflight, Inc., 814 F.2d 1506, 1511 n.4 (identifying the EEOC guideline as "[o]ne possible index of substantial disparity"); cf. M aldonado, 433 F.3d at 1305 ("EEOC guidelines, while not controlling upon the courts by reason of their authority, do constitute a body of experience and inform ed judgm ent to which courts and litigants m ay properly resort for guidance." (internal quotation m arks om itted)). W hat the large num ber of standard deviations m eans is that the departure from equality, w hatever its magnitude, is highly unlikely to be random. Of course, when there are m assive disparities, the difference m ay be m any standard deviations. But when, as here, there is a great deal of data, even a relatively sm all difference m ay be highly statistically significant (that is, unlikely to be random). Consider an experim ent involving 1,000,000 flips of a coin. The canonical result, of course, would be 500,000 heads and 500,000 tails. Say, the

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results were 510,000 heads and 490,000 tails. Although the magnitude of the difference is sm all, only about 4% m ore heads than tails, the odds of such a difference occurring in the absence of a weighted coin are exceedingly sm all-- the departure from equality is 20 standard deviations. The difference strongly indicates som e influence on the results other than the operation of pure chance. Likewise, under the Siskin Study's analysis, it is very, very unlikely that the difference in the assignm ent of overtim e to m en and w om en w ith the sam e job, grade, budget code, and shift is a random event. As the Siskin Study observed, "Clearly, som ething in the overtime process consistently results in males obtaining more overtime and working more overtime than females." R. Doc. 346 at 23. The large number of standard deviations tells us nothing about what that "som ething" is, however, other than that it is not based on differences in job, grade, budget code, or shift. As a result, it could be very im portant, contrary to Plaintiffs' brief, that nearly a quarter of the overtim e opportunities were in work done by only one person if, as im pliedly assum ed in the above-quoted passage from Plaintiffs' brief, men disproportionately held those positions or the offers of overtim e w ere concentrated in such positions held by m en. (In such situations there is very little, if any, supervisor discretion in the assignm ent of overtim e, because the CBA provides that the person who norm ally perform s the work should be offered it first.) Similarly, it could be quite im portant if men are disproportionately -39-

em ployed in crew s in w hich overtime is available to everyone in the unit. Of course, such gender disparities in these positions could indicate discrim ination in hiring for those jobs, but that is not the claim m ade by Plaintiffs. See Price v. City of Chicago, 251 F.3d 656, 661 (7th Cir. 2001) (plaintiff's statistical showing that eligibility test may produce disparate im pact could not establish prim a facie case w hen the test's use is not the em ploym ent practice com plained of). An illustration m ay m ake this proposition clearer. Boeing's expert, Dr. W ard, conducted a study on overtime assignments that controlled for the CBA criteria by surveying individual managers about the actual offers m ade to eligible employees. For each overtim e assignm ent, Dr. W ard's study determ ined who was eligible under the CBA and then m easured whether m en were disproportionately selected for the overtim e. These data were collected for only a portion of the W ichita facility and only for a two-m onth period in 2003, so the study is hardly dispositive of whether discrim ination occurred. But the results are instructive. W hen only one employee norm ally perform ed the work and was eligible for the overtim e assignm ent, wom en received 14% (76 of 535) of the overtim e offers, precisely what would be expected (according to the report) given their representation in the jobs from which those overtim e assignm ents were m ade. W hen multiple workers were eligible under the CBA for the assignm ent, wom en received 23% (430 of 1855) of the offers, very slightly more than would be expected. Overall, w om en received 21% (506 of 2390) of the overtim e offers. -40-

From these data it appears likely that wom en were significantly underrepresented in those jobs for w hich only one w