How to perform a preplanned process evaluation for complex interventions in geriatric medicine: exemplified with the process evaluation of a complex falls-prevention program for community-dwelling frail older fallers.

Complex interventions are difficult to develop, document, evaluate, and reproduce. Process evaluations aid the interpretation of outcome results by documenting and evaluating each process step in detail. Despite its importance, process evaluations are not embedded in all evaluations of complex interventions. Based on literature, we structured the process evaluation for trials on complex interventions into 3 main components: (1) the success rate of recruitment and quality of the study population, (2) the quality of execution of the complex intervention, and (3) the process of acquisition of the evaluation data. To clarify these process evaluation components and measures, we exemplified them with the preplanned process evaluation of a complex falls-prevention program for community-dwelling frail older fallers and their informal caregivers. The 3 process evaluation components are operationalized, results are presented, and implications discussed. This process evaluation identified several limitations of the intervention and effect study, and resulted in multiple recommendations for improvement of both the intervention as well as the trial. Thus, a good-quality process evaluation gives a detailed description of the most important components of a complex intervention, resulting in an in-depth insight in the actually performed intervention and effect analysis. This allows us to draw the appropriate conclusions on positive or negative trial results, and results in recommendations for implementation, or adjustment of the intervention or effect evaluation, respectively.