The Cost-Time Index: a new method for measuring the efficiencies of recruitment-resources in clinical trials.

Paid media are important resources used to recruit subjects in clinical trials. An index for evaluating which advertising resource has minimal cost and time requirement for patient accrual, for a given study design, has not been previously introduced. In this communication the authors present a new index, the Cost-Time Index, which represents a measure of the average amount of money and time spent, simultaneously, on a given advertising resource to recruit one analyzable subject.