Adverse Impact in Employment Law: Four-Fifths Rule and EEOC Filing

Adverse impact in employment happens when a hiring, promotion, or other selection practice looks neutral on its face but ends up screening out people in a protected group at a significantly lower rate than others. The employer’s motive is not the issue; the outcome is. The concept comes from Title VII of the Civil Rights Act of 1964 and is one of the most common ways employment discrimination claims reach the Equal Employment Opportunity Commission and the federal courts.

Where the Rule Comes From

Title VII bars employment discrimination based on race, color, religion, sex, and national origin.¹ It also reaches policies that appear neutral but produce discriminatory effects.²

The Supreme Court first recognized this in Griggs v. Duke Power Co. in 1971. Duke Power required a high school diploma and passing scores on two aptitude tests for certain positions, and neither requirement predicted job performance. The Court unanimously struck the requirements down, holding that Title VII targets the consequences of employment practices, not just intent.³

Congress wrote the framework into the statute in the Civil Rights Act of 1991. A disparate impact claim is made out when a plaintiff shows that a particular employment practice causes a disproportionate effect on a protected group and the employer cannot show the practice is job-related and consistent with business necessity.⁴ Even when the employer clears that bar, the plaintiff can still prevail by pointing to an equally effective alternative practice that would produce less of a discriminatory effect.⁵

How Adverse Impact Is Measured: The Four-Fifths Rule

The main screening tool is the four-fifths rule, sometimes called the 80% rule, from the federal Uniform Guidelines on Employee Selection Procedures. A selection rate for any race, sex, or ethnic group that falls below four-fifths of the rate for the highest group is generally treated as evidence of adverse impact.⁶

The math is simple. Divide the number of people selected from each group by the number of people from that group who applied or were considered. That gives you each group’s selection rate. Then divide each group’s rate by the highest group’s rate. If any result comes out below 0.80, the rule is triggered.

For example, if 60% of white applicants pass a screening test and 40% of Black applicants pass the same test, 40 divided by 60 is about 0.67. That’s well under 0.80, and the test warrants a closer look.

When the Four-Fifths Rule Isn’t Enough

The rule is a starting point, not a verdict. The Uniform Guidelines themselves note that greater differences in selection rates may not amount to adverse impact when the numbers involved are small and the gap is not statistically significant.⁶ A pool of five applicants and three hires cannot really support the calculation.

Courts think along the same lines. With small samples, judges typically want a statistical significance test alongside the four-fifths analysis. A common benchmark is a p-value of 0.05 or lower, roughly a two-standard-deviation gap between expected and observed outcomes. Without that added rigor, a four-fifths shortfall by itself may not carry a prima facie case.

Practices That Commonly Cause Problems

The practices most likely to create adverse impact tend to look reasonable in isolation. That’s why employers who aren’t checking their outcomes get surprised.

Standardized aptitude tests. Written tests of cognitive ability or general aptitude have a long history of producing score gaps across racial and ethnic groups. If the test hasn’t been validated against actual job performance, it is vulnerable.
Educational requirements. Demanding a college degree for a role that doesn’t genuinely need one can screen out applicants from lower-income backgrounds, which often correlates with race and ethnicity. That was the issue in Griggs.
Physical fitness tests. Strength or agility requirements that aren’t tied to real job demands can disproportionately exclude women and people with disabilities.
Narrow experience windows. Asking for a tight band of experience, say four to seven years, can exclude older workers with longer careers and younger workers who haven’t hit that range.
Criminal history screens. Blanket disqualifications based on any criminal record tend to affect certain racial groups disproportionately. EEOC guidance says employers using criminal history must consider the nature and gravity of the offense, the time that has passed, and the nature of the job. Arrests alone, without looking at the underlying conduct, generally cannot justify exclusion.⁷

Each of these measures something other than the ability to do the job. When that something correlates with a protected characteristic, selection rates diverge.

Adverse Impact vs. Disparate Treatment

These two theories live in the same statute but operate differently. Adverse impact is about outcomes. No one has to prove that a manager was biased or acted with discriminatory purpose. The question is whether a facially neutral practice produced a lopsided result for a protected group.

Disparate treatment is about intent. An employer who refuses to hire women for warehouse jobs, or who steers Latino applicants away from customer-facing roles, is treating people differently because of who they are. The plaintiff’s burden is to show that the protected characteristic was a motivating factor in the decision.

The distinction matters for remedies. Compensatory and punitive damages are available when the employer acted with intent. In a pure adverse impact case, with no discriminatory motive, relief is generally limited to equitable remedies such as back pay and policy changes.

What the Employer Has to Prove

Once a plaintiff shows that a particular practice causes disparate impact, the burden shifts to the employer to prove the practice is job-related and consistent with business necessity.⁵ This isn’t a casual showing. The employer needs evidence that the practice actually predicts or measures something essential to performing the job, not that it’s convenient or traditional.

The Uniform Guidelines recognize three ways to validate a selection procedure: statistical correlation between test scores and job performance, direct sampling of important job tasks or knowledge, and measurement of a psychological trait genuinely necessary for the job. Employers using testing or structured assessments should have that validation on hand before a challenge, not after.

Even a validated practice can lose. If the plaintiff identifies an alternative practice that serves the employer’s legitimate needs equally well with less adverse impact, the employer can still be liable. The plaintiff carries that burden, but in practice it means employers should think about less exclusionary alternatives before locking in a selection method.⁵

What a Worker Can Recover

When an employer loses an adverse impact case, a court can order equitable relief: back pay covering lost wages (limited to two years before the charge was filed), reinstatement or placement into the position the plaintiff should have held, and an injunction requiring the employer to stop using the practice.⁸ Where reinstatement isn’t practical, courts sometimes award front pay to compensate for future lost earnings.⁹

Compensatory damages for emotional harm and punitive damages are only available when intentional discrimination is proven, not in a pure adverse impact claim.¹⁰

Filing a Charge With the EEOC

Someone who believes an employer’s practice has produced adverse impact must file a charge with the EEOC before filing a lawsuit. The general deadline is 180 calendar days from the discriminatory act, extended to 300 days if a state or local agency enforces a law prohibiting the same type of discrimination.¹¹ Weekends and holidays count toward the deadline, but if the last day falls on a weekend or holiday, the deadline rolls to the next business day.

Charges can be filed through the EEOC’s online Public Portal after submitting an inquiry and completing an interview. The agency then investigates, which may include requesting a position statement from the employer and reviewing hiring data.¹² Missing the filing deadline forfeits the right to pursue the claim, so track dates from the moment you become aware of a potentially discriminatory practice.

Employer Record-Keeping

Employers have their own obligations that make adverse impact analysis possible. Under the Uniform Guidelines, each employer should keep records showing the impact its selection procedures have on employment opportunities by race, sex, and ethnic group.⁶ If the employer fails to maintain that data and a group is underrepresented in a job category, enforcement agencies can draw an inference of adverse impact from the missing records alone.

Private employers must keep application forms, hiring records, pay information, and similar documents for at least one year from the date the record was made or the personnel action occurred, whichever is later. Records tied to an involuntary termination must be kept for one year from the termination date. State and local government employers and educational institutions face a two-year retention period.¹³

Once a charge is filed, the rules tighten. The employer must preserve all personnel records relevant to the charge until the matter is fully resolved, whether by dismissal, settlement, or final judgment.¹³ Destroying records after a charge lands is one of the fastest ways to turn a defensible case into a losing one.

1
U.S. Equal Employment Opportunity Commission. Title VII of the Civil Rights Act of 1964
2
U.S. Department of Justice. Laws We Enforce
3
Justia U.S. Supreme Court Center. Griggs v. Duke Power Co.
4
U.S. Equal Employment Opportunity Commission. Civil Rights Act of 1991 – Original Text
5
Office of the Law Revision Counsel. 42 U.S. Code 2000e-2 – Unlawful Employment Practices
6
eCFR. 29 CFR 1607.4 – Information on Impact
7
U.S. Equal Employment Opportunity Commission. Enforcement Guidance on the Consideration of Arrest and Conviction Records in Employment Decisions Under Title VII of the Civil Rights Act
8
Office of the Law Revision Counsel. 42 U.S. Code 2000e-5 – Enforcement Provisions
9
U.S. Equal Employment Opportunity Commission. Front Pay
10
Office of the Law Revision Counsel. 42 U.S. Code 1981a – Damages in Cases of Intentional Discrimination
11
U.S. Equal Employment Opportunity Commission. Time Limits for Filing a Charge
12
U.S. Equal Employment Opportunity Commission. Filing a Charge of Discrimination
13
eCFR. 29 CFR Part 1602 – Recordkeeping and Reporting Requirements Under Title VII