Statistics and the Law: Hypothesis Testing and Its Application to Title VII Cases Louis J
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Hastings Law Journal Volume 32 | Issue 1 Article 2 1-1980 Statistics and the Law: Hypothesis Testing and Its Application to Title VII Cases Louis J. Braun Follow this and additional works at: https://repository.uchastings.edu/hastings_law_journal Part of the Law Commons Recommended Citation Louis J. Braun, Statistics and the Law: Hypothesis Testing and Its Application to Title VII Cases, 32 Hastings L.J. 59 (1980). Available at: https://repository.uchastings.edu/hastings_law_journal/vol32/iss1/2 This Article is brought to you for free and open access by the Law Journals at UC Hastings Scholarship Repository. It has been accepted for inclusion in Hastings Law Journal by an authorized editor of UC Hastings Scholarship Repository. Statistics and the Law: Hypothesis Testing and Its Application to Title VII Cases By Louis J. BRAUN* Statistics1 form a useful tool in the determination of whether defendants in a Title VII action2 have engaged in employment dis- crimination.3 Statistics also can determine whether disparities in the form of an underrepresentation of minority group members in particular jobs or differences in pay, benefits, or conditions of em- * Associate Professor of Mathematics and Statistics, Pace University, New York, New York. B.A., 1963, New York University;, Ph.D., 1971, City University of New York. The author wishes to thank Donald H. Zeigler and Donald L. Doernberg, Associate Professors of Law, Pace University School of Law, for their helpful suggestions in the prepa- ration of this Article. 1. Statistics may be defined loosely as the collection, correlation, and interpretation of data. For a detailed explanation of statistical analysis see, D. HUNTSBERGER, D. CROFT & P. BILLINOSLEY, STATISTICAL INFERENCE FOR MANAGEMENT AND ECONOMICS (2d ed. 1980) [here- inafter cited as HUNTSBERGER]. 2. Title VII of the Civil Rights Act of 1964, as amended, 42 U.S.C. §§ 2000e to 2000e- 17 (1976 & Supp. H 1978), makes it unlawful for an employer "to fail or refuse to hire or to discharge any individual or otherwise to discriminate against any individual with respect to his compensation, terms, conditions, or privileges of employment, because of such individ- ual's race, color, religion, sex, or national origin .... ." Id. § 2000e-2(a)(i). In addition to governmental agencies and departments, private parties have causes of action under Title VII that allow them to recover damages for injuries sustained as a result of discriminatory treatment directed against them as employees or potential employees. See Johnson v. Good- year Tire & Rubber Co., 491 F.2d 1364 (5th Cir. 1974). 3. See, e.g., Dothard v. Rawlinson, 433 U.S. 321 (1977) (hiring practices); T.I.M.E.- D.C., Inc. v. United States, 431 U.S. 324 (1977) (hiring and promotion practices); Interna- tional Bhd. of Teamsters v. United States, 431 U.S. 324 (1977) (hiring and promotion prac- tices); Griggs v. Duke Power Co., 401 U.S. 424 (1971) (hiring and transfer policies); Donald- son v. Pillsbury Co., 554 F.2d 825 (8th Cir.), cert. denied, 434 U.S. 856 (1977) (layoff and termination policies); EEOC v. Local 14, Int'l Union of Operating Eng'rs, 553 F.2d 251 (2d Cir. 1977) (union membership policies); Wetzel v. Liberty Mut. Ins. Co., 508 F.2d 239 (3d Cir.), cert. denied, 421 U.S. 1011 (1975) (promotion practices); Pettway v. American Cast Iron Pipe Co., 494 F.2d 211 (5th Cir. 1974) (promotion and transfer policies); Jones v. Lee Way Motor Freight, Inc., 431 F.2d 245 (10th Cir. 1970), cert. denied, 401 U.S. 954 (1971) (promotion and transfer policies); Johnson v. University of Pittsburgh, 359 F. Supp. 1002 (W.D. Pa. 1973) (layoff and termination policies). THE HASTINGS LAW JOURNAL [Vol. 32 ployment can be attributed solely to chance factors. Plaintiffs often have relied on statistical analysis to meet the initial burden of establishing a prima facie case of discrimination.4 Defendants too have used statistics to show, among other things, that the em- ployment practices which are alleged to be discriminatory amounted to bona fide job requirements5 or to rebut the statistical evidence offered by plaintiffs.6 In International Brotherhood of Teamsters v. United States,1 the Supreme Court recognized the importance of statistical analysis in cases in which the existence of discrimination is a disputed issue.8 Furthermore, statistics showing an extraordinarily small number of minority employees have been held to establish a violation of Title VII as a matter of law.9 Some courts nevertheless have shown a reluctance to use sta- tistics in employment discrimination cases, either because they did not understand the analysis, found the theory too complicated,10 or 4. In McDonnell Douglas Corp. v. Green, 411 U.S. 792, 802 (1973), the Court held that in a private Title VII action, the plaintiff will satisfy the burden of establishing a prima facie case of discrimination if he or she shows: "(i) that he belongs to a racial minority; (ii) that he applied and was qualified for a job for which the employer was seeking applicants; (iii) that, despite his qualifications, he was rejected; and (iv) that, after his rejection, the position remained open and the employer continued to seek applicants from persons of com- plainant's qualifications." In subsequent cases, courts have held that the plaintiff need not have applied for the position if he or she can show that, given the defendant's conduct, such an act would be futile. See, e.g., Rodriguez v. East Texas Motor Freight Sys., Inc., 505 F.2d 40, 55 (5th Cir. 1974), vacated on other grounds, 431 U.S. 395 (1977). In such "disparate treatment" cases, proof of the defendant's discriminatory motive is critical although it may be inferred from the mere fact of differences in treatment. See International Bhd. of Teamsters v. United States, 431 U.S. 324, 355 n.15 (1977). However, courts also have held that prima facie cases of employment discrimination can be estab- lished, by both private and governmental plaintiffs, by showing that the defendant's policies had a "disparate impact" on minorities without having to prove that the defendant in- tended to discriminate. Id. Disparate impact analysis focuses on the consequences of the defendant's employment practices, not the motives behind them. A prima facie case of discrimination can be established by statistical evidence alone. Rodriguez v. East Texas Motor Freight Sys., Inc., 505 F.2d 40, 53 (5th Cir. 1974), vacated on other grounds, 431 U.S. 395 (1977). In disparate impact cases, where the motives of the defendants are irrelevant, statistics can be especially useful in establishing a prima facie case of discrimination. See, e.g., Dothard v. Rawlinson, 433 U.S. 321 (1977); Griggs v. Duke Power Co., 401 U.S. 424 (1971). 5. See, e.g., Dothard v. Rawlinson, 433 U.S. 321 (1977); Spurlock v. United Airlines, Inc., 475 F.2d 216 (10th Cir. 1972). 6. See, e.g., Hazelwood School Dist. v. United States, 433 U.S. 299 (1977); Ochoa v. Monsanto Co., 335 F. Supp. 53 (S.D. Tex. 1971), aff'd, 473 F.2d 318 (5th Cir. 1973). 7. 431 U.S. 324 (1977). 8. Id. at 339. 9. Parham v. Southwestern Bell Tel. Co., 433 F.2d 421, 426 (8th Cir. 1970). 10. See, e.g., Allen v. City of Mobile, 331 F. Supp. 1134, 1139 n.14 (S.D. Ala. 1971). September 1980] STATISTICS AND THE LAW because the results were not grounded in absolute certainty.11 Even those courts accepting statistical analysis, but forced to rely on the interpretations and understandings of expert witnesses, sometimes express a wariness and discomfort in using statistics to resolve le- gal issues.12 In InternationalBrotherhood of Teamsters, for exam- ple, the Court stated: "We caution only that statistics are not irref- utable; they come in infinite variety and, like any other kind of evidence, they may be rebutted. In short, their usefulness depends on all of the surrounding facts and circumstances." 3 Although sta- tistics can be misused in developing an aura of support for a posi- 1 tion not supportable by the evidence, 4 rather than bar or severely curtail its use, steps can and should be taken to impose restrictions which would disallow its improper use only. If the rudiments of statistical analysis were understood by the courts, they would have a better perception of what constitutes its proper use and could exercise a more constructive control over its admissibility as evidence. This Article discusses a limited but central area of statistical anaylsis applicable to Title VII cases.1 5 Although the techniques and theories developed herein all have been used by expert wit- nesses in such cases, their synthesis into a cohesive theory of evi- dence should foster a greater understanding and thus a more pro- ductive use of statistics in employment discrimination litigation. The focus of the Article will be on the field of statistical analy- sis known as hypothesis testing,16 with an initial discussion of the problems in determining the proper population of available em- 11. See, e.g., Chance v. Board of Examiners, 458 F.2d 1167, 1173 (2d Cir. 1972). 12. A large measure of the distrust with which courts often view statistics stems from the popular reputation of statistics as being an analytical device that can be used to twist the truth and prove whatever it is one wants to prove. See, e.g., D. HuFF, How To LIE WrrH STATISTIcs (1954). 13. 431 U.S. at 340. 14. See HUNTSBERGER, supra note 1, at 4-8. 15. This Article is not intended to offer a complete and detailed account of each and every statistical technique that can be used in a Title VII action, but rather to present and explain the most useful of the analytical techniques which apply to such cases.