This document discusses metrics for evaluating the effectiveness and cost of different hiring sources. It presents data on the cost per hire, number of applications and hires, and quality of source for six different sources. Source E and F had the highest quality of source, defined as the percentage of applicants worth further review. The document recommends doubling down on sources E and F based on this data, which resulted in tripling the number of hires and cutting cost per hire in half. It also discusses implementing metrics to hold recruiters accountable for missed interviews and hires to improve the candidate experience and motivate recruiters.