—from the Epidemiological Bulletin, Vol. 20 No. 1, March 1999—

Methodological Summaries: Measuring Inequity in Health

The aim of this new section of the Epidemiological Bulletin is to provide in a regular basis a series of methodological considerations and tools available for its application in epidemiology. In this issue, the section begins with a summary on tools for measuring inequity in health.

Introduction

Equity in health is considered to be a basic principle for human development and social justice. With a view to guiding its programs and providing its technical assistance, the Pan American Health Organization is increasingly concerned about how to achieve higher levels of equity in countries undergoing different social, health and economic reforms, such as those of the Region of the Americas.

Debate on what constitutes equity in health is currently under way in various national and international forums (WHO/PAHO, world banks, health foundations, national governments, universities and research centers). Likewise, efforts committed in the search for methods and indicators to measure equity in health are increasing. Considering the high degree of social inequity in the Region of the Americas, the available empirical information has to be used to document the Region’s progress in this endeavor.

Inequity versus Inequality

The concept of inequity has been considered synonymous with the concept of inequality; however, it is fundamental to differentiate between the two. While inequality implies differences between individuals or population groups, inequity refers to differences which are unnecessary and avoidable but, in addition, are also considered unfair and unjust. Not all inequalities are unjust, but all inequities are the product of unjust inequalities. The definitions of just and unjust are subject to various interpretations. In the context of health, one of the more accepted definitions of "just" refers to equal opportunities for individuals and social groups, in terms of granting access to and using the health services, in accordance with the needs of the various groups of a population, regardless of their ability to pay.

Measuring Socioeconomic Inequity

The indicators used to measure social inequity in health can be classified as measurements of effect and total impact. On the one hand, measurements of effect are used to analyze fixed categories from a health variable; for example, pregnant women with no prenatal care versus pregnant women receiving complete prenatal care. On the other, measurements of total impact are used to analyze proportions of the population, using a socioeconomic variable. Continuing with the previous example, a measurement of total impact would involve the comparison of the health variable (prenatal care) for the poorest quintile (20%) of the female population versus the same variable for the richest quintile of that population.

There are several methods for quantifying relative differences in the distribution of a socioeconomic indicator. The classic one is the Gini coefficient, used extensively in Economics to measure the degree of inequity in terms of a population’s income distribution. The Gini coefficient is based on the Lorenz curve, which indicates the cumulative frequency for comparing a variable’s empirical distribution with its uniform distribution (equality). This uniform distribution is represented by a diagonal line. Consequently, the more distance between the Lorenz curve and the diagonal line, the greater the inequality. The Gini coefficient measures the degree of inequity, summarizing the deviation shown of the Lorenz curve with respect to the diagonal line (representing equality). The possible values of the Gini coefficient range from zero to one. The indicator would be equal to zero in conditions of perfect equity; for example, when income is distributed equally among all individuals of society. This procedure and indicators can also be applied to health issues.

The Nordic countries (Finland, Norway and Sweden) have the most equitable distribution of income, with Gini coefficient values ranging between 0.25 and 0.30. The average Gini coefficient for the world as a whole is 0.40. However, the countries of the world with the highest levels of inequity in terms of income distribution, have a Gini coefficient on the order of 0.60. In 1995, for example, the Gini coefficient for the countries of Latin America was estimated at 0.58.

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Epidemiological Bulletin, Vol. 20 No. 1, March 1999

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