Development of Questionnaire on Willingness-to-Pay for Health Insurance Cost-Sharing for Catastrophic Prescription Drugs

Prescription drug cost-sharing in Indonesia remains challenging because no valid willingness-to-pay (WTP) questionnaire for this cost-sharing is available. The aim of this study was to conduct item selection and evaluate the content validity of the questionnaire on the WTP for prescription drug cost-sharing under the national health insurance scheme in patients with catastrophic illnesses. The method was a cross-sectional study and used a three-step design, namely literature review, consultation with some health economics experts, and evaluation of content validity. This study involved 9 experts, consisting of academicians and health professionals who worked in a hospital, to perform content validation of a questionnaire on the WTP for prescription drug cost-sharing. This study used CVI (content validity index) and CVR (content validity ratio) for both individual item measurement and the overall scale. This study's results reveal a questionnaire comprising 47 items grouped into five domains: healthcare utilization information, participation in health insurance information, drug information, and cost-sharing scenarios. The questionnaire items were extracted from many sources. The items that could be used for the study should have an I-CVI of 0.79-1.00. There were three items removed because of criticisms from the experts and Item-CVI<0.79 and CVR<0.62. Those with Item-CVI>0.79 were revised. The overall scale of the questionnaire was excellent with an S-CVI/Ave of 0.94. We conclude that the questionnaire on the willingness-to-pay for prescription drug cost-sharing was developed and validated through expert consultation, item selection, and CVI. The questionnaire reviewed in this study had good content validity. As a follow-up, a new 42-item questionnaire was developed.