How do you calculate the four-fifths rule?

Divide each group's selection rate (number selected ÷ number of applicants) by the selection rate of the highest group. If the result is below 0.80, adverse impact is indicated. Example: a 30% selection rate divided by a 50% rate equals 0.60, which is below 0.80 and triggers a flag.

Does the four-fifths rule apply only to hiring?

No. It applies to any selection procedure, including promotions, layoffs, pre-employment tests, physical or education requirements, and background screens. A four-fifths flag shifts the burden to the employer to show the practice is job-related and consistent with business necessity.

Texas HR Compliance

What is the four-fifths (80%) rule for Texas employers?

Q: What is the four-fifths (80%) rule?

It is the EEOC's rule of thumb for detecting adverse impact in selection procedures. If a protected group's selection rate is less than 80% (four-fifths) of the highest group's selection rate, the practice is flagged as potentially discriminatory in effect — even without discriminatory intent.

The four-fifths rule is the math the EEOC uses to spot when a hiring, promotion, or layoff practice screens out a protected group — even when the practice looks perfectly neutral. It's one of the few compliance tools you can run yourself, before a decision becomes a charge.

Last updated: July 12, 2026

Direct Answer

The four-fifths rule — also called the 80% rule — comes from the EEOC's Uniform Guidelines on Employee Selection Procedures. It flags potential adverse impact: if the selection rate for a protected group is less than 80% of the rate for the highest-selected group, that's evidence a practice may be discriminatory in effect, even without intent. To calculate it, divide each group's selection rate by the highest group's rate; a result under 0.80 is a warning sign that shifts the burden to you to show the practice is job-related and necessary.

What This Means for Employers

Most Texas employers think about discrimination as intent — someone deciding not to hire a person because of who they are. The four-fifths rule is about the other kind, the kind you can commit by accident. Under the disparate-impact theory in Title VII, a hiring test, an education requirement, a physical standard, or a background screen can be unlawful because of how it lands across groups, regardless of what you meant by it. The four-fifths rule is the screening math that surfaces that pattern.

The calculation is simple enough to do on a spreadsheet. Take each group's selection rate — the number selected divided by the number who applied — and compare it to the group with the highest rate. Say 50 of 100 male applicants are hired (a 50% rate) and 30 of 100 female applicants are hired (a 30% rate). Divide 30% by 50% and you get 60%. Because that's below 80%, the rule flags adverse impact against women in that hiring round. The same math applies to promotions, to test pass rates, and to who gets selected — or cut — in a layoff.

What the rule does not do is prove discrimination. A flag is the start of the conversation, not the verdict. But once a practice trips it, the legal posture changes: you're now expected to show the requirement is genuinely job-related and consistent with business necessity. If you can't, a neutral-sounding policy becomes a liability.

What Employers Usually Miss

The first thing employers miss is that this reaches far past the job application. The four-fifths rule applies to any "selection procedure" — promotions, reductions in force, physical or skills tests, minimum education or experience screens, and blanket background, credit, or criminal-history checks. Employers audit their hiring and never think to run the same math on how they chose who to lay off, which is often where the sharpest exposure sits.

The second miss is timing. The rule is most valuable before you roll something out. If you're about to introduce a new pre-employment test, a lifting requirement, or an automated résumé screen, you can model its impact on your applicant pool first and fix it while it's still cheap. Employers who only discover adverse impact after an EEOC charge are doing the analysis in the worst possible order.

The third miss is small numbers. The four-fifths ratio gets unstable with tiny samples — in a group of six, one different decision swings the percentage wildly. A small business can trip or clear the rule on a single hire, which means the flag has to be read with judgment, not treated as an automatic conclusion. That nuance is exactly where employers either over-react or ignore a real signal.

Avoidable Risks in Selection-Procedure Compliance

These are the practices that most often generate adverse-impact exposure:

Pre-employment tests or assessments that were never validated against the actual job
Blanket criminal-history, credit, or background screens applied without individualized, job-related justification
Physical or education requirements that exceed what the role actually demands
Layoff or promotion criteria that were never checked for disparate impact
No applicant-flow or selection data, leaving you unable to run the analysis or defend a practice
Reading a four-fifths flag from a very small sample as either proof or non-issue, instead of applying judgment

What to Review Before You Act

Before you launch or keep relying on any screen, run the four-fifths math on your own recent data — hires, promotions, and any layoff rounds — broken out by the protected groups you can track from applicant and workforce records. Where a group falls below 80%, treat it as a prompt to examine the specific practice driving the gap.

Then test each screen against the job itself. Ask whether the requirement measures something the role actually needs, and whether you could defend it as job-related and necessary if challenged. Keep the underlying data — applicant flow, selection decisions, the rationale for each requirement — because an adverse-impact defense lives or dies on records you either kept or didn't. If you're introducing something new, model its impact before it touches a single candidate.

When to Get HR Help

Get support when a screen trips the four-fifths rule and you're not sure whether the cause is the practice or the sample size, because reacting to the wrong one is costly either way. It's also worth help when you're rolling out a new test, an automated hiring tool, or standardized layoff criteria — that's the moment to validate for impact, and it's far cheaper than defending the tool after a charge.

For Texas employers without in-house HR analytics, an outside review can run the calculations, separate real signals from small-sample noise, and document the job-relatedness of the screens you keep — which is the record that protects you if the EEOC ever asks.

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Catch Adverse Impact Before It Becomes a Charge

Faulkner HR Solutions helps Texas employers run the four-fifths analysis on their real hiring, promotion, and layoff data — and document the job-relatedness of the screens worth keeping. Connect with us to pressure-test your selection procedures.

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Written and reviewed by Dr. Thomas W. Faulkner, DBA, MBA, MSML, SPHR, LSSBB, principal consultant at Faulkner HR Solutions, a Texas HR consulting firm based in San Antonio serving small businesses, nonprofits, municipalities, and public sector employers.

This page provides general HR information for employers and is not legal advice. For legal interpretation or representation, consult qualified employment counsel.