Terminology

One problem facing the committee was that the nomenclature for concepts and measures of population health derives from a number of literature streams, and the committee found itself at a confluence of these streams, where the same names were being applied to quite different things. For purposes of this report, a measure of population health can involve mortality data (e.g., age-adjusted mortality rates for a given year, life expectancy at birth or age 65) or morbidity data (e.g., disability rates or quality of life indices) or both. The focus of the report is on summary measures of population health that combine both mortality and morbidity data to represent overall population health in a single number (e.g., a health-adjusted life year or health-adjusted life expectancy).

Figure 1 depicts how mortality and morbidity measures—as partial measures of population health—combine to form an integrative measure. The background paper by Fryback describes the process in more detail.

FIGURE 1 Building a summary measure from partial measures of health.

Because measures of health-related quality of life (HRQL) are important building blocks of these integrated measures and generate much of the controversy about these measures, such measures are also considered in this report and the background papers. To depict an individual’s overall health at a particular time, these measures generate a single number on a scale anchored by 0 (state of being dead) and 1 (state of optimal health) that represents the degree or strength of preferences for one health state over another. For some purposes including cost-effectiveness analysis, measures of health-related quality of life must be based on utilities or preferences for health states that meet the conditions of welfare economics, which assumes that individuals seek to maximize utilities (preferences for particular outcomes) and that overall societal welfare is some function of these individual utilities.

A variety of other measures of health status have been developed. One broad category of measures constructs profiles of people’s health along one or more dimensions. The measures include the SF-36, the 36-item short-form of the Medical Outcomes Study survey created from the Rand General Health Survey (Brook et al., 1979) and the Sickness Impact Profile (Bergner, 1981). Because such profiles do not yield a single summary number from, for example, scores representing physical or mental functioning, these measures of health status have not been combined with life expectancy measures to form an integrative summary measure of population



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