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A general measure of population health is useful for comparing the health status of a population over time, or between populations at a single point in time. It permits comparisons of health systems and programmes, and may highlight populations in need of particular attention from health services. 1
The infant mortality rate (IMR), defined as the number of deaths in children under 1 year of age per 1000 live births in the same year, has in the past been regarded as a highly sensitive (proxy) measure of population health. 2 This reflects the apparent association between the causes of infant mortality and other factors that are likely to influence the health status of whole populations such as their economic development, general living conditions, social well being, rates of illness, and the quality of the environment.
More recently it has been argued that proxy measures of population health like IMR are problematic 3 ; and the past decade has seen IMR fall out of favour. The World Health Report 2000 , 4 for example, makes no reference to the measure.
Despite starting as indicators of a whole population's health, measures like IMR often, it is reasoned, become the principal focus of health policy such that health strategies and health priorities are formulated with the proxy outcome measure in mind. 3 As a consequence, health policies begin to target the chosen outcome measure, while ignoring the rest of the population for which the outcome measure was supposed to be an indicator. Thus, IMR may decrease, as infant mortality becomes the principal focus of health policy, but the whole population's health may, unknown to the ministries of health, remain static or even degrade.
This view has lead to the development of more comprehensive measures of population health; for example, the disability adjusted life expectancy (DALE). 5 Such measures are intended to (a) be sensitive to changes of health in the whole population, and (b) account for the morbidity associated with non-fatal health outcomes as well as mortality. 1
The argument about the dangers of using IMR as a measure of population health has intuitive appeal, highlighting the fact that it derives from a small, non-representative portion of the population and excludes any consideration of non-fatal health outcomes. In...