Measuring inequalities in access to health care: a review of the indices?

Equity in health care is a goal embraced by most industrialized countries. Although universal coverage of health care services does not eliminate inequalities, it represents the first step towards a more equitable health care system. This paper explores the main methodological issues involved in defining and measuring equity in access to health care. Access, equity and need are complicated concepts which are difficult to define and to measure. The definition of equity most appropriate for policy makers is that of equal access for equal need. There is no consensus about the definition of need, although most commonly ill-health is used to indicate need for health care, because of relative ease of measurement. Access is a multi-dimensional concept influenced by both supply and demand factors; however it is commonly approximated by utilization which is easily observed. Methodological issues arise in the simplification of these complex terms; for instance, the measurement of utilization alone to define access leaves out other important factors such as quality of care, and cultural and financial barriers, which are necessary in understanding inequalities. Most countries use surveys and/or administrative sources to measure access and need. However, each of these methods faces inherent limitations. Surveys collecting data on utilization or self-assessed health are subject to bias based on questionnaire design, question wording and psychosocial and cultural factors. Administrative sources on the other hand are less able to collect information on health status, and might be limited in their coverage of other important indicators. Generally, there are three main approaches to calculating equity in access to health care, these are: 1) odds ratios, 2) rates of access and use-needs ratios, and 3) horizontal inequity index. Although increasingly surveys are available at EU-level, more work is needed to improve these surveys and collect more comprehensive and reliable information on both health and access to health care.