How to use the four-fifths rule
The four-fifths rule compares how often people from different groups are selected. Under the federal Uniform Guidelines adopted in 1978, a rate below 80% of the highest group's rate signals potential adverse impact. Use the calculation to review hiring, promotions, training selections, and workforce reductions.
About this note
Published Reviewed
For US employers reviewing hiring, promotions, training opportunities, and workforce reductions. Uniform Guidelines on Employee Selection Procedures, 29 CFR 1607.4(D).
At a glance
Compare each group's selection rate with the highest rate. The 1978 Uniform Guidelines use 80% as a screening threshold for potential adverse impact. A result below that threshold calls for closer review of the selection process and underlying numbers.
Research reviewed: Executive Order 14281 and the Justice Department opinion issued 9 June 2026.
- 1978
- The year four federal agencies adopted the Uniform Guidelines.
- Below 80%
- A threshold for closer review of selection rates.
Calculate the four-fifths ratio
Gather the number of people considered and selected in each group. Calculate the percentage selected within each group, rather than its share of the applicant pool. There are four steps.
- Calculate each selection rate. Divide the number selected by the number considered. If 48 of 80 applicants are selected, the selection rate is 60%.
- Find the highest selection rate. Use this as your benchmark.
- Calculate the impact ratio. Divide each group's selection rate by the highest rate. For example, a 42% selection rate divided by the highest rate of 60% produces a ratio of 0.70, or 70%.
- Compare the result with 80%. A ratio below 80% calls for a closer review of the underlying numbers and selection process.
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Includes an Adverse-Impact Review comparing selection rates by age, sex, and race or ethnicity. Use it to identify groups that warrant review before finalizing a workforce reduction.
A hiring example
Here is how the calculation works for two groups applying for the same role.
- Highest selection rate 60%
- The group with the highest selection rate had 80 applicants and 48 offers. 48 divided by 80 is 0.60, so the rate is 60%. Use 60% as the comparison rate.
- Compared group 42%
- The second group had 50 applicants and 21 offers. 21 divided by 50 is 0.42, so the rate is 42%.
- Impact ratio 0.70, below the 80% threshold
- 42% divided by 60% is 0.70, or 70%. Because 70% is below the 80% threshold, examine the selection criteria and steps that produced the difference.
If the second group received three additional offers, it would have 24 offers out of 50 applicants. Its selection rate would be 48%, producing a ratio of exactly 80%.
What the result tells you
The four-fifths ratio flags differences for review. A ratio at or above four-fifths can still count as adverse impact when the difference is significant in statistical and practical terms. A ratio below four-fifths may not count when it rests on small numbers that are not statistically significant. The underlying counts and selection process help you interpret the result.
Identify the specific selection practice that produced the difference. Examine how the practice relates to the job and whether another effective approach could produce a smaller disparity. Under Title VII, these questions are part of the legal framework for evaluating disparate-impact claims.
Document the underlying counts, selection criteria, and ratio for every group, including those at or above 80%.
When to use the calculation
Use the four-fifths calculation for hiring, promotions, training selections, and workforce reductions. Define who was eligible for each decision, then calculate the percentage selected. In a workforce reduction, for example, compare the percentage retained in each group.
The same approach works for selection rates produced by resume screening software, assessments, AI hiring software, and other hiring technology. Review these results alongside the rest of the selection process.
Why sample size matters
In a small group, one selection decision can change the ratio substantially. The guidelines recognize that a difference based on small numbers may not be adverse impact when it is not statistically significant. Examine the underlying counts and consider statistical significance before drawing conclusions. Three details deserve attention.
- Small applicant groups. Review the underlying counts and consider a statistical significance test before drawing conclusions. For employers with more than 100 employees, the guidelines call for analysis at least annually for any group that makes up 2% or more of the labor force in the relevant labor area or of the applicable workforce.
- The highest selection rate. Find the highest rate for each selection process. Recalculate the benchmark for each hiring cycle because it can change.
- The comparison group. Use the people eligible and considered for the decision. For hiring, that means the relevant applicants. For promotions, use the eligible candidates. For a workforce reduction, use the employees within the defined selection pool.
Federal enforcement and the law
Four federal agencies adopted the Uniform Guidelines on Employee Selection Procedures in 1978. The four-fifths rule comes from those guidelines. It appears in 29 CFR 1607.4(D).
A 2025 executive order changed federal enforcement priorities. Executive Order 14281, signed 23 April 2025, directed federal agencies to deprioritize disparate-impact enforcement and to review or unwind matters built on the theory. Disparate impact is written into Title VII by the Civil Rights Act of 1991, and the Supreme Court recognized it in 1971 in Griggs v. Duke Power Co. Private plaintiffs can still bring disparate-impact claims, and several state laws, including those in California, New York, and Illinois, keep the theory in force.
On 9 June 2026, the Justice Department's Office of Legal Counsel issued an opinion at the request of the EEOC chair.
The opinion concludes that the EEOC's longstanding disparate-impact guidelines are unconstitutional as applied. Under the opinion, disparate-impact evidence should primarily support claims of intentional discrimination rather than serve as a freestanding basis for liability.
It reads the business necessity defense to require only that an employment practice rationally serve a valid business purpose.
The opinion binds federal executive-branch enforcement. It leaves Title VII, Griggs, and the 1991 Act unchanged. Federal courts, private plaintiffs, and state agencies remain outside its reach.
Employers can continue to compare selection rates, identify meaningful differences, and document how selection criteria relate to the work.
Include the four-fifths calculation when reviewing hiring, promotions, and workforce reductions. When a result is flagged, identify the selection practice responsible and confirm that it is job related before relying on it.
Research and sources
5 research sources. Reviewed 13 October 2026.
- Uniform Guidelines on Employee Selection Procedures, 29 CFR 1607.4(D). The federal regulation establishing the four-fifths comparison. A selection rate below 80% of the highest group's rate is generally regarded as evidence of adverse impact. Statistical and practical significance can affect how results are interpreted. Adopted jointly in 1978 by the EEOC, Civil Service Commission, Department of Labor, and Department of Justice. Source: ecfr.gov, 29 CFR 1607.4. Checked: 13 October 2026.
- Title VII disparate impact, 42 U.S.C. 2000e-2(k). The statutory framework added by the Civil Rights Act of 1991, which makes disparate impact unlawful and sets the burden-shifting test. The claimant shows that a specific employment practice causes a disparate impact. The employer must then show the practice is job related and consistent with business necessity. The claimant may still prevail by showing an effective alternative with less discriminatory impact was available. The doctrine also traces to Griggs v. Duke Power Co., 401 U.S. 424 (1971). Source: law.cornell.edu, 42 U.S.C. 2000e-2. Checked: 2 June 2026.
- EEOC, Employment Tests and Selection Procedures. The agency’s guidance explains that determining whether a selection procedure has a disparate impact ordinarily requires a statistical analysis. A flagged procedure must then be shown to be job related and consistent with business necessity. eeoc.gov, employment tests and selection procedures
- Executive Order 14281, Restoring Equality of Opportunity and Meritocracy. Signed 23 April 2025, 90 FR 17537. Directed federal agencies to deprioritize disparate-impact enforcement and review related matters. Source: federalregister.gov, EO 14281. Checked: 21 July 2026.
- Department of Justice, Office of Legal Counsel, Constitutionality of Disparate-Impact Liability Under Title VII. Opinion issued 9 June 2026. Concludes that the EEOC's disparate-impact guidelines are unconstitutional as applied and interprets the role of intent and the business necessity defense for federal executive-branch enforcement. Source: justice.gov, OLC opinion of 9 June 2026 (PDF). Checked: 8 October 2026.
Common questions
What is the four-fifths rule in plain terms?
The four-fifths rule compares how often people from different groups are selected. If one group's selection rate is below 80% of the highest group's rate, review the selection steps and underlying counts. The calculation comes from the 1978 federal Uniform Guidelines and is also called the 80% rule.
What should I do when a result falls below 80%?
Start by identifying the selection practice behind the difference. Assess whether it is job related and consistent with business necessity, and consider whether a less discriminatory alternative was available but not used.
Is the four-fifths rule still in effect after the 2025 executive order?
Yes. The four-fifths provision remains in the federal Uniform Guidelines. Executive Order 14281 changed federal enforcement priorities in April 2025, while Title VII and the Civil Rights Act of 1991 remained unchanged. The 1991 Act wrote disparate impact into Title VII, and the Supreme Court also recognized it in Griggs.
A June 2026 Justice Department opinion treats impact mainly as evidence of intent for federal enforcers and binds only the executive branch. Private lawsuits and several state laws continue to recognize disparate impact.
Employers can continue using the calculation to identify selection practices worth reviewing and confirm that flagged practices are job related.
Does the rule work for a small team?
Yes. Start with the actual counts. When only a few people are involved, one selection decision can change the ratio substantially. Consider statistical significance alongside the four-fifths calculation, particularly for consequential decisions.
Does it apply to layoffs and promotions, or only hiring?
Yes. Promotions, training selections, and employees retained during a workforce reduction all produce selection rates you can compare. The calculation also applies to automated screeners and AI hiring tools when reviewing selection rates for adverse impact.
Tools for the next step
Enter the number considered and selected for each group. See selection rates, impact ratios, and groups below the 80% threshold.
FreeIncludes an Adverse-Impact Review comparing selection rates by age, sex, and race or ethnicity. Use it to identify groups that warrant review before finalizing a workforce reduction.
$129Review AI hiring software and other hiring technology, document risks, and evaluate selection rates across groups. The checklist includes a written policy and a workbook assigning Low, Medium, or High risk ratings to each tool. The governance kit adds a four-fifths check, vendor bias audit request, candidate notice, and adverse impact review memo.
$89Compare a proposed promotion with the new pay range and employees already in the role. Identify potential pay compression with the level above.
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