Page 34 - The Importance of Common Metrics for Advacing Social Science Theory and Research

The Importance of Common Metrics for Advancing Social Science Theory and Research: A Workshop Summary
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22 THE IMPORTANCE OF COMMON METRICS

MEASURING HEALTH-RELATED QUALITY OF LIFE
Dennis Fryback (University of Wisconsin, Madison) introduced a ty-
pology for health measures and then focused on the need for standardized
“health-related quality of life” (HRQoL) indexes.
In his basic typology of health measures, Fryback distinguished be-
tween mortality-based and morbidity-based measures. Mortality-based
measures are among the easiest to ascertain—life expectancies, whether
someone is alive or dead. Morbidity measures and nonfatal outcomes are
more difficult to track. The health field tends to rely on morbidity indicators
that are usually countable (e.g., tuberculosis rate, Caesarian section rate,
percentage of the population that exercises). He briefly reviewed examples
of morbidity-based indicators, including Healthy People 2010, the Core
Health Indicators of the World Health Organization (WHO), America’s
Health Rankings, and the Wisconsin County Health Rankings. Many of
these measures either contain too many indicators for a useful overall as-
sessment of progress (e.g., Healthy People 2010, WHO) or arbitrarily sum
several indicators to get rankings of states to stimulate policy. Fryback
argued for less arbitrary ways of summarization.
One level up are summary health status measures that proxy point-
in-time summaries of a person’s health, but with respect to a particular
disease or organ. They are sensitive to changes in symptoms or functional
impairment due to a particular disease process. Examples include the Ar-
thritis Impact Measurement System (AIMS), the Vision Function Question-
naire, the McGill Pain Questionnaire, and the New York Heart Association
Classification.
There are also generic health status measures that aim to obtain a
full-spectrum profile of an individual’s health. These use a relatively brief
questionnaire that touches on all of the major domains of health (or at least
the relatively agreed-on ones) and is not tied to just one disease or organ
system. These are useful particularly in measuring the health of people who
have multiple disease conditions. The ubiquitous measure throughout the
world is perhaps the SF-36 health profile, Fryback said. Its 36 questions
8
cover 8 domains of health, with separate scores generated for each of two
subscales: the physical component and the mental component.
Of all the generic health status indexes, Fryback favors the HRQoL to
represent the overall health of the individual. The scale or score is neither
a simple, psychometric sum of items nor a sum of responses to items on a
questionnaire. Instead, it reflects preferences for different aspects of health,
with 1 = perfect health and 0 = dead. Econometric methods are used to
8 The eight domains included in the SF-36 are physical function, role functioning as affected
by physical abilities, bodily pain, general health, vitality, social functioning, role functioning
as affected by emotional health, and mental health.

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