What is adverse impact?

How adverse impact is defined

Adverse impact is a term from the Uniform Guidelines on Employee Selection Procedures (UGESP), which the Equal Employment Opportunity Commission, the Civil Service Commission, the Department of Labor, and the Department of Justice adopted together in 1978. The EEOC's version is codified at 29 CFR part 1607. Section 1607.16 defines adverse impact as "a substantially different rate of selection in hiring, promotion, or other employment decision which works to the disadvantage of members of a race, sex, or ethnic group." A selection rate is the proportion of applicants or candidates who are hired, promoted, or otherwise selected. This summary reflects federal sources as of November 11, 2026. This page is a general overview, not legal advice.

The four-fifths rule: Section 1607.4(D) sets the rule of thumb most teams use. "A selection rate for any race, sex, or ethnic group which is less than four-fifths (4/5) (or eighty percent) of the rate for the group with the highest rate will generally be regarded by the Federal enforcement agencies as evidence of adverse impact."

For example, if 60 of 100 applicants in one group are selected (60%) and 30 of 80 in another group are selected (37.5%), the impact ratio is 37.5 divided by 60, or 0.625. That is below 0.8, so the guidelines would generally treat it as evidence of adverse impact.

The guidelines treat the rule as a starting point, not a final test. Smaller differences can still count when they are significant in both statistical and practical terms. Larger differences may not count when they rest on small numbers and are not statistically significant. Other parts of the guidelines say that:

• A selection procedure with adverse impact is considered discriminatory unless it has been validated or otherwise justified under the guidelines (section 1607.3(A)).
• When two procedures are similarly valid, the one with lesser adverse impact should be used (section 1607.3(B)).
• Employers should keep records that show the impact of their selection procedures by sex and by race or ethnic group (section 1607.4(A) and (B)).
• The guidelines cover hiring, promotion, referral, retention, and other employment decisions (section 1607.2(B)).

Adverse impact is closely related to disparate impact, the legal theory in Title VII of the Civil Rights Act. Under 42 U.S.C. 2000e-2(k), a practice that causes a disparate impact is unlawful if the employer cannot show it is job related for the position and consistent with business necessity. It is also unlawful if the complaining party shows an alternative employment practice and the employer refuses to adopt it. The impact ratios that NYC Local Law 144 requires in bias audits apply the same idea.

Why adverse impact matters for talent teams

Federal policy on adverse impact is changing. As of November 11, 2026:

• Executive order: Executive Order 14281, signed April 23, 2025, directs federal agencies to deprioritize enforcement of statutes and regulations to the extent they include disparate-impact liability, including Title VII.
• Justice Department opinion: On June 9, 2026, the Justice Department announced an Office of Legal Counsel opinion to the EEOC concluding that the EEOC's disparate-impact guidelines are unconstitutional.
• Other agencies: The Office of Personnel Management removed references to the guidelines from federal civil service regulations, effective July 31, 2026. The Department of Labor's rescission of the Executive Order 11246 regulations, effective October 26, 2026, removed its version of the guidelines at 41 CFR part 60-3.
• EEOC: The EEOC's regulatory agenda lists a final rule to rescind the interpretive portions of 29 CFR part 1607, with final action projected for November 2026 and an effective date in January 2027. As of November 11, 2026, that rule has not been published in the Federal Register, and part 1607 remains in the Code of Federal Regulations.

The disparate impact provision in Title VII is set by statute, and these agency actions do not amend it. State and local rules also apply, so many talent teams still calculate selection rates and impact ratios at each hiring stage to see where differences arise.

How Findem approaches adverse impact

Findem's guide to AI governance in HR recommends measuring adverse impact at the role level first. It lists selection rates by job family and role, differences across demographic groups, intersectional effects where possible, four-fifths-rule checks, and changes over time after model or process updates. Pooled results can mask harm in a specific role, which is why the guide calls for disaggregated audits.

In December 2025, Findem completed an independent bias audit of its applicant-matching practices with Warden AI. The audit found that those practices met Warden AI's fairness thresholds across key groups.

Findem is the People Intelligence Platform. Its AI does not reject candidates or make hiring decisions, and people review results before they influence hiring decisions. Whether a selection procedure has adverse impact, and what follows from it, is a question for each employer and its counsel.

Further reading

• AI governance in HR: A practical guide
• Findem completes independent AI bias audit with Warden AI
• AI hiring laws in 2027: What Colorado, Connecticut, and California require