Design of process evaluation within the Child and Adolescent Trial for Cardiovascular Health (CATCH).

Process evaluation complements outcome evaluation by providing data to describe how a program was implemented, how well the activities delivered fit the original design, to whom services were delivered, the extent to which the target population was reached, and factors external to the program that may compete with the program effects. The process evaluation system used in the Child and Adolescent Trial for Cardiovascular Health (CATCH) is presented in this paper. The conceptual model underlying the CATCH process evaluation system is described, and process measures and data collection protocols are reviewed. Functions of process evaluation data in the trial include: (1) describing the implementation of the program, (2) quality control and monitoring, and (3) explaining program effects. The importance of incorporating process evaluation into final outcome analyses and assessments of program impact is emphasized.