Introduction

A health system should be evaluated against the fundamental goal of ensuring that individuals in need of health care receive effective treatment. One way to evaluate progress towards this goal is to measure the extent to which access to health care is based on need rather than willingness or ability to pay. This egalitarian principle of equity or fairness is the primary motivation for health systems' efforts to separate the financing from the receipt of health care as expressed in many policy documents and declarations (Judge et al. 2006; van Doorslaer et al. 1993). The extent to which equity is achieved is thus an important indicator of health system performance.

Measuring equity of access to care is a core component of health system performance exercises. The health system performance framework developed in WHO's The world health report 2000 stated that ensuring access to care based on need and not ability to pay is instrumental in improving health (WHO 2000). It can also be argued that access to care is a goal in and of itself: ‘beyond its tangible benefits, health care touches on countless important and in some ways mysterious aspects of personal life and invests it with significant value as a thing in itself’ (President's Commission for the Study of Ethical Problems in Medicine and Biomedical and Behavioural Research, 1983 cited in Gulliford et al. 2002).