Probabilistic polling and voting in the 2008 presidential election: evidence from the American Life Panel

Publication type

Journal Article


Publication date

June 1, 2010


 This article reports new empirical evidence on probabilistic polling,
which asks persons to state in percent-chance terms the likelihood that
they will vote and for whom. Before the 2008 presidential
election, seven waves of probabilistic questions
were administered biweekly to participants in the American Life Panel
Actual voting behavior was reported after the
election. We find that responses to the verbal and probabilistic
questions are
well-aligned ordinally. Moreover, the probabilistic
responses predict voting behavior beyond what is possible using verbal
responses alone. The probabilistic responses have
more predictive power in early August, and the verbal responses have
power in late October. However, throughout the
sample period, one can predict voting behavior better using both types
of responses
than either one alone. Studying the longitudinal
pattern of responses, we segment respondents into those who are consistently pro-Obama, consistently anti-Obama, and undecided/vacillators.
Membership in the consistently pro- or anti-Obama group is an almost
perfect predictor of actual voting behavior, while
the undecided/vacillators group has more nuanced
voting behavior. We find that treating the ALP as a panel improves
power: current and previous polling responses
together provide more predictive power than do current responses alone.

Published in

Public Opinion Quarterly

Volume and page numbers

Volume: 74 , p.433 -459






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