Use of time studies for determining intervention costs

Background: Cost-effectiveness analyses are increasingly recommended to evaluate the effectiveness of health interventions. Determining the costs associated with delivery of a particular intervention is essential in conducting a cost-effectiveness analysis. Yet, there are few guidelines available to assist investigators in how to assess intervention costs associated with the personnel portion of an intervention. Objectives: To describe the use of time studies in calculating the program costs of personnel for use in future cost-effectiveness analysis of health interventions. Methods: The literature on calculating intervention costs for use in cost-effectiveness analyses is reviewed. The process for conducting a time study for determining personnel costs in delivering an intervention and a step-by-step example from a time study are used to illustrate how personnel costs associated with delivery of the intervention can be separated from those costs associated with implementation of research procedures in the determination of research costs. Conclusions: Time studies provide a good estimate of part of the cost of implementing an intervention that is often difficult to determine - personnel time. The design of the time study should consider intervention components, staff involvement, and the time period for data collection.