Page 49 - 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
http://www.nap.edu/catalog/13034.html

INDICATORS 37

of what is being examined may determine what measurement standards
are used.
Turning to disability measures, Pollak considered as a real barrier to
progress the lack of consistency in the concept and definition of disability
and in the analysis of trends in prevalence. Some clarification on what is
meant by the term “disability” is needed, he said, since different defini-
tions suggest different kinds of solutions and indicate different targets for
interventions and actions. Pollak further stated that it is unclear in this case
what standardization will achieve.
He observed that public perceptions would certainly be affected by the
standardization of disability and that policy may even be affected. How-
ever, questions remain: What should be the basis for standardization? What
should be the underlying assumptions? Should the definition of disability be
more or less inclusive? In Pollak’s view, whether standardized measurement
would lead to better policy can be discussed only in terms of a particular
standardization of measurement and a particular view of what constitutes
better policy.
In economics, theory has implications for measurement, and econo-
mists regard measurement without theory with skepticism (Koopmans,
1947). Pollak used the example of the consumer price index (CPI) and the
cost of living index to examine the use of standardized measurements for
disability. The crucial aspect of having a theory is that it provided a way
of dealing with a lot of hard problems that arose in constructing the CPI.
The underlying theory provides a framework to refer to when questions
arise that challenge the components of the index. Pollak posed the question:
What counts as an argument if there is no theory to appeal to? Without a
theory, he asserted, anything is equally as good as a treatment of a difficult
problem. He further stated that another main advantage of theory is that
it depoliticizes some of the serious choices that do have impacts on the
behavior of the index.
Turning to the issue of how disability is perceived, Pollak divided the
literature into three sections: (1) disability among children, (2) disability
among working-age adults, and (3) disability among the elderly. Using the
example of activities of daily living (ADLs), such as transferring, dressing,
bathing, toileting, eating, and walking across a room, Pollak proposed that
if individuals or their proxies were asked which activities pose difficulties,
an index could be derived by adding up the number of positive responses.
However, the questions of how the items in this index were chosen and how
their weight was determined are significant. For example, does the standard
list of ADLs give too little weight to cognitive impairment relative to mo-
bility impairment? How is it determined if a new item needs to be added
to the ADL list and, if it is, what weight is it assigned? Pollak argued that

Copyright © National Academy of Sciences. All rights reserved.