Dear all,
Please join us for the Applied Statistics Workshop (Gov 3009) this
Wednesday, October 17 from 12.00 - 1.30 pm in CGIS Knafel Room 354. James
Scanlan <http://www.jpscanlan.com/homepage.html>, an Attorney at Law, will
give a presentation entitled "The Mismeasure of Group Differences in the
Law and the Social and Medical Sciences". As always, a light lunch will be
provided.
Abstract:
This paper addresses the problematic nature of efforts in the law and the
social and medical sciences to appraise the
comparative circumstances of
advantaged and disadvantaged groups on the basis of standard measures of
differences in outcome rates, given that such measures tend to be
systematically affected by the prevalence of an outcome. The rarer an
outcome the greater tends to be the relative difference in experiencing it
and the smaller tends to be the relative difference in avoiding it. Thus,
for example, as mortality declines relative differences in mortality of
advantaged and disadvantaged groups tend to increase while relative
differences in survival tend to decrease; as procedures like immunization
and cancer screening become more common, relative differences in rates of
receipt of those procedures tend to decrease while relative differences in
rates of failing to receive them tend to increase; relaxing mortgage
lending criteria tends to increase relative differences in mortgage
rejection rates while reducing relative differences in mortgage approval
rates. Similarly, among subpopulations where adverse outcomes are
comparatively rare (e.g., persons with high education or high income,
British civil servants), relative differences in adverse outcomes tend to
be larger, while relative differences in favorable outcomes tend to be
smaller, than among subpopulations where adverse outcome are more common.
Absolute differences between outcome rates and differences measured by odds
ratios are unaffected by whether one examines the favorable or the adverse
outcome. But such measures tend also to be affected by the overall
prevalence of an outcome, though in a more complicated way than the two
relative differences. Broadly, as uncommon outcomes become more common
absolute differences tend to increase; as already common outcomes become
even more common, absolute differences tend to decrease. Differences
measured by odds ratios tend to change in the opposite direction of
absolute differences as the prevalence of an outcome changes. The paper
will explain these patterns and the misinterpretations of data on group
differences arising from the failure to understand them. It will also
describe a method for appraising the size of the difference in
circumstances reflected by outcome rates of advantaged and disadvantaged
groups that is theoretically unaffected by the prevalence of the outcome.
An up-to-date schedule for the workshop is available at
http://www.iq.harvard.edu/events/node/1208.
Best,
Konstantin
--
Konstantin Kashin
Ph.D. Candidate in Government
Harvard University
Mobile: 978-844-0538
E-mail: kkashin(a)fas.harvard.edu
Site:
http://www.konstantinkashin.com/<http://people.fas.harvard.edu/%7Ekkashi…