Self-reported health care utilization: measurement issues, data validity and implications for design of health surveys and economic evaluations An empirical investigation among patients with diabetes mellitus

Objectives: 1. To develop, test and refine a questionnaire collecting data on health care utilization in patients with diabetes. 2. To develop methods for a validation study quantifying the accuracy of self-reported health care utilization data. Methods: The questionnaire on health care utilization was developed and tested by a combination of behavior coding and cognitive interviews in 43 patients with diabetes mellitus types 1 and 2 in Germany. Theoretical considerations and empirical evidence with regard to validity of self-reported health care utilization were reviewed. Results: The questionnaire on health care utilization for use in diabetes research in Germany was developed and refined after careful testing. Only few studies investigated how to improve accuracy of self-reported health care utilization. To this end, it was decided to validate the questionnaire for two different recall periods applying an experimental design. Conclusion: More experimental studies, i.e. randomized allocation of participants to different questionnaire modes, recall periods, etc. are needed to better quantify the benefits of various data collection methods.