Page 39 - 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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MEASUREMENT IN THE SOCIAL SCIENCES 27

ment of medical care output is highlighted by the fact that current measure-
ment approaches result in reported negative productivity growth in the U.S.
medical care industry. This is an area in which improved measurement does
not depend on economic theory. What are needed are measures of medical
outcomes, like those Fryback discussed. Triplett added that there are many
cases in economics in which improvement of an economic measurement
depends on getting information from other social and natural sciences.
In her discussion, Kathleen Cagney (University of Chicago) distilled
some of the main points from Fryback’s presentation and focused on chal-
lenges and opportunities related to the measurement of HRQoL. Turning
attention to the three classes of HRQoL measures—generic health indices
and profiles, disease-specific measures, and preference-based measures—
and their interplay, Cagney considered how generic and disease-specific
measures focus on the presence, absence, severity, frequency, or duration of
symptoms and how these are drawn from psychometric theory, whereas the
preference-based measures relevant for assessing preferences of individuals
for alternative health states or outcomes are drawn from economic theory
and ideas of comprehensiveness and comparability.
Cagney referred to the seminal work of Patrick and Erickson (1993),
which defines HRQoL as the value assigned to duration of life as modified
by impairments, functional states, perceptions, and social opportunities that
are influenced by disease, injury, treatment, or policy. In contrast, the defini-
tion offered by the Centers for Disease Control and Prevention assumes that
HRQoL is synonymous with health status but also encompasses reactions
to coping with life circumstances.
Cagney referred also to the objectives of health status assessment as
outlined by Patrick and Erickson (1993): to discriminate among persons at
a single point in time, to predict some future outcome or results of a more
intrusive or costly criterion measure, and to measure change over time
(e.g., cohort study). Consistent with the tenor of Fryback’s presentation,
Cagney shared Colleen McHorney’s (1999) observation that the “field of
health status assessment is regarded more for how it quantifies and validates
health status indicators than for how and why it conceptualizes health.”
Cagney considered the SF-36 a standard in health status assessment. It is
responsive to 44 disease conditions, and it has been translated into more
than 50 languages. However, as McHorney has pointed out, there are 8,360
different ways to score 50 on the SF-36 physical functioning scale, which
is only half of the SF-36 measure. What is important in Cagney’s view is to
consider the progression of disease over the life course and how one shifts
from the initial position of health decline to a later state of physical frailty.
Cagney summarized a number of challenges associated with the HRQoL
measure. She highlighted Fryback’s sense that HRQoL scores describe but
do not actually value health, a goal that may be informed by the work of

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