The same hiring round,
at two decimals and at four
Type your round in. The tool computes the selection rate for each group and the ratio between them, then shows the verdict the four-fifths rule of thumb gives at the precision your report prints, next to the one it gives at the precision the arithmetic has.
Free. No signup, no email, no AI. It runs in your browser and nothing you type is sent anywhere or stored.
For example, candidates who asked for an adjustment.
Everyone else in the same round.
At or above 0.80: not flagged.
Below 0.80: flagged for review.
The two boxes disagree. Rounding to two decimals carried the ratio onto the threshold, and the verdict with it.
The working
Group A rate: 6 / 22 = 27.2727 % Group B rate: 14 / 41 = 34.1463 % Impact ratio: lower rate / higher rate = 0.798701 Threshold the four-fifths rule of thumb uses: 0.80 Rounded to two decimals: 0.80 To four: 0.7987
What it means when the two boxes disagree
The four-fifths rule is a screening rule of thumb, not a legal test and not a statistical test. What this page shows is narrower than any of that: whether the verdict your report gives depends on how many decimals it kept. A ratio of 0.7987 is below 0.80. Printed as 0.80 it is not. Nothing about the round changed; the precision did.
When the two boxes disagree, the precision is the finding. The right response is not to pick the friendlier box. It is to record the ratio at four places, name the round, and hand the question to the person who owns the decision.
Where this check comes from
The numbers pre-filled here are the assessment-round fixture: 6 of 22 candidates in one group advanced against 14 of 41 in the other, for an impact ratio of 0.7987 against a threshold of 0.80. In the pack, the agent that prepares the adverse-impact check is instructed to print the ratio to four places and never to round onto the threshold, and its answer key holds this exact case.
The check is one of the fixtures in The HR AI Stack. You do not need the pack to use this page. That is the point of publishing the page.
AI can prepare a people decision. It cannot own it.
Practitioner guidance, not legal advice. The four-fifths rule of thumb is one screening convention among several and its standing varies by jurisdiction and year; check the rule your organisation and its counsel actually apply before acting on any verdict, including this page's.
The other checks in this family: The biggest discount that still holds the floor · A tolerance with two limbs, and the one that binds · Re-add the bridge, get the residual · The instructions you pasted, counted against the ones you tested · All free tools