# The four-fifths rule

The four-fifths rule is a guideline stating that if a group's selection rate in hiring falls below 80 percent of the rate for the group with the highest selection rate, it may be regarded as evidence of adverse impact.

This is a general description of the rule, not legal advice; whether it applies to a specific situation is a legal question.

**The four-fifths rule** — The four-fifths rule comes from the Uniform Guidelines on Employee Selection Procedures and provides a statistical threshold for flagging possible adverse impact. It states that the selection rate for any group should be compared to the selection rate for the group with the highest rate; if that ratio falls below four-fifths, or 80 percent, it may be regarded as evidence of adverse impact. As an example of the calculation: if 60 percent of one group's applicants are selected and 50 percent of another group's applicants are selected, the ratio is 50 divided by 60, or about 83 percent, above the 80 percent threshold. If the second group's rate dropped to 40 percent instead, the ratio would fall to about 67 percent, below the threshold. The rule is a practical screening tool, not a strict legal test on its own; falling below 80 percent flags a practice for closer review rather than automatically establishing a violation, and passing the 80 percent threshold doesn't automatically clear a practice from further scrutiny either.

Employers and analysts use the four-fifths rule as a first-pass statistical check across a hiring pipeline, applied at any stage where a selection decision happens: application to interview, interview to offer, or the overall hire rate. It's most useful as an early signal, prompting a closer look at whether a specific stage or criterion is producing an uneven outcome across groups, rather than as a final determination of legal compliance, which depends on factors beyond the ratio itself.

## Frequently asked questions

### Does failing the four-fifths rule automatically mean discrimination occurred?

No. It's a statistical screening threshold that flags a practice for closer review. Whether an actual violation occurred depends on additional legal factors, including whether the practice is job-related and consistent with business necessity.

### How is the four-fifths ratio actually calculated?

Divide the selection rate of the group with the lower rate by the selection rate of the group with the highest rate. If the result is below 0.8, or 80 percent, the practice may be flagged as evidence of adverse impact under the rule.

### Where does the four-fifths rule come from?

It originates in the Uniform Guidelines on Employee Selection Procedures, a framework federal agencies use for evaluating whether an employment selection procedure has an adverse impact on a protected group.

## Related pages

- [Adverse impact](/glossary/adverse-impact)
- [EEOC compliance](/glossary/eeoc-compliance)
- [Browse open roles](/jobs)

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