The ratio is found by dividing the number of candidates interviewed for a role by the number of offers made. If a team interviews twelve people to make two offers, the ratio is 6:1. It is often tracked by stage, for example first-round to final interview, and by hiring manager or role family, which shows where interview time is being spent on candidates who were never likely to receive an offer.
Every interview costs hours from hiring managers and panel members, so a high ratio is an expensive signal. Common causes are vague requirements, a screening step that passes too many people forward or a manager whose expectations shifted mid-search. Agreeing criteria at intake and screening every applicant against them consistently usually brings the ratio down without narrowing the pool unfairly.