Effect of specificity of health expenditure questions in the measurement of out-of-pocket health expenditure: Evidence from field experimental study in Ghana

Background: The effect of number of health items on OOPs has been identified as a source of bias in measuring OOPs. Evidence comes mostly from cross-sectional comparison of different survey instruments to collect data on OOPs. Very few studies have attempted to validate these questionnaires, or distinguish bias arising from the comprehensiveness of the OOPs list versus specificity of OOPs questions.

Objectives: This study aims to estimate biases arising from the specificity of OOPs questions by comparing provider and household’s information.

Methods: A generic questionnaire to collect data on household’s OOPs was developed following the nomenclature proposed in division 6 of the COICOP2018. The four categories within such division are used to set the comprehensiveness of the OOPs list, the specificity within each category was tailored to the design of the nationally representative living standard survey in Ghana where a field experiment was conducted to test the validity of differ...