Cost per hire
Cost per hire is the total recruiting spend for a period divided by the number of hires made, including advertising, agency fees, tooling, referral bonuses and often an allocation of recruiter time.
It is a budgeting metric rather than a quality metric, and optimising it in isolation is a well-known trap — the cheapest hire and the best hire are frequently not the same person.
Read alongside quality of hire and first-year attrition, it becomes more useful.