Although equity in health has been understood in different ways, in practical terms its pursuit involves the elimination of systematic health disparities between more and less socially advantaged population groups.1 International efforts toward greater health equity generally have focused on reducing the dramatic disparities between better- and worse-off nations; however, accumulating evidence also reveals large health disparities between social groups within countries of diverse per-capita income levels.2- 5 In rich and poor countries, social advantage varies according to socioeconomic status, race/ethnicity, sex, age, and location. Unfortunately, available information on social disparities in health within most countries comes from time-limited research projects rather than ongoing information systems. Routine health information in most countries, particularly poor countries, is ill suited to identifying within-country health disparities.
Routine health statistics usually reflect population averages, which can hide large gaps between groups. For example, during 1994-1996, the US infant mortality rate overall was 7.6% per 1000 live births; however, among African Americans, it was 15.2% per 1000, more than twice the rate among whites (6.3% per 1000).5 The overall rate of stunted growth among Brazilian children during 1996 was 10.5%; among children in the lowest economic quintile the rate was 23.2%, 10 times that among the wealthiest quintile.4 Many lower-income countries now have upper and middle classes whose living conditions are increasingly similar to those in affluent countries, alongside large groups who remain deeply impoverished.6 Aggregate statistics mixing these subpopulations can obscure very disparate health and health care experiences.
Vital records in lower-income countries rarely contain socioeconomic information. Furthermore, the data available for assessing health equity in lower-income countries are often biased, painting a misleading picture of population needs. While of questionable quality in most countries, cause-of-death information is particularly unreliable for poor groups in poor countries.7 Births and deaths are substantially under-reported in many poor countries, particularly among disadvantaged groups. In many lower-income nations, births and deaths are registered only by location of occurrence, not residence. Because rural residents often go to cities to give birth and/or to die, vital statistics cannot be used to determine how birth outcomes or mortality vary by place of residence7; thus, interventions cannot be targeted to the appropriate areas.
The challenges of obtaining and interpreting information on social inequalities in health have prompted some researchers to propose abandoning these efforts.8 The World Health Report 2000 measured what it called "health inequalities" by comparing the magnitude of differences in health between healthier and sicker—but not richer and poorer—individuals.8 By contrast, measuring social inequalities in health requires measuring differences in health between better- and worse-off social groups. The distinction has considerable practical importance. Only by comparing social groups can one understand how health is differentially distributed in a population, which groups to target for interventions, or how to allocate resources to achieve greater equity. Without information on social inequalities in health and how they change over time, one cannot assess the effects of policies that could influence equity in health.1,9
Despite these challenges, promising approaches are available and being tested to assess social disparities in health in countries of all income levels.3,4,7 For example, some surveys on low-income countries already contain both health and social information, which permits estimates of social inequalities4; socioeconomic information is also being added to other existing surveys. The Global Equity Gauge initiative is supporting development in some countries of new local, provincial, and national surveys that include both socioeconomic and health information; some even describe the perceived quality of available health services, disability, or quality of life [http://www.hst.org.za/hlink/equitypub/gega.htm]. Obtaining reliable population-based information on social disparities in health and health care within countries is challenging, but feasible—and a necessary step toward achieving equity in health.
Braveman P. Measuring Health Equity Within Countries: The Challenge of Limited Information. JAMA. 2002;288(13):1650. doi:10.1001/jama.288.13.1650-JMS1002-4-1