[gov3009-l] Gov 3009 February 19: Glickman

Elizabeth Stuart stuart@stat.harvard.edu
Sun, 16 Feb 2003 15:58:25 -0500 (EST)

This week's speaker at the Gov 3009 seminar is Mark Glickman, speaking on
"Combining Speed and Accuracy to Assess Error-free Cognitive

The paper can be found at: http://math.bu.edu/people/mg/papers/spacc.ps,
and an abstract follows.  More information on the seminar can be found

Many experiments on human cognition involve having a subject
make a judgment as quickly and accurately as possible. Both reaction times
and error rates are widely used indices of human performance in such
experiments.  A difficulty in relying on either one of these indices alone
is the problem of a speed/accuracy tradeoff; subjects who react quickly
are more likely to have higher error rates, whereas subjects who are more
accurate are likely to have slower reaction times. Another difficulty
arises when subjects respond slowly and inaccurately (rather than quickly
but inaccurately), e.g., due to a lapse of attention.  We introduce an
approach that combines response time and accuracy information that
addresses both situations.  The modeling framework assumes two latent
competing processes.  The first, the error-free process, always produces
correct responses.  The second, the residual process, results in all
observed errors and some of the correct responses (but does so via
non-specific processes, such as guessing in compliance with instructions
to respond on each trial). Inferential summaries of the speed of the
error-free process provide a principled assessment of cognitive
performance reducing the influences of both fast and slow guesses.
Likelihood analysis is discussed for the basic model and extensions.  This
is joint work with Jeremy Gray (Washington Univ in St. Louis), and Carlos
Morales (Worcester Polytechnic Institute).

Seminar Information:
The seminar meets at noon in Room 22, Center for Basic Research
in Social Sciences (CBRSS, 34 Kirkland St., this is the yellow building
across the street from William James Hall). Contact information, previous
presentations, and the spring schedule may be found at the course web
site: http://www.courses.fas.harvard.edu/~gov3009/.  Lunch is provided.

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Questions?  Please contact the workshop coordinator, Liz Stuart, at