Pundits are double-counting voter enthusiasm.

Ed Kilgore points out that a lot of the predictions of a rout in November rely on double-counting voter enthusiasm.

Ed Kilgore’s post on the November Congressional makes a lot of good points; the whole thing is worth a read.

But what struck me most was this:

much of the “overestimation” of Democratic strength in past generic polls has involved early tests with no “likely voter” screen. As we get closer to Election Day, the Gallup generic ballot is usually quite accurate (as shown some years ago by TDS contributor Alan Abramowitz of Emory). So it’s not a good idea to just mentally add a few points to Gallup’s number for the GOP and assume that’s close to reality.

This is worth more stress than Ed gives it.  Likely voter screens try to figure out who will vote in November so as to poll only them.  (Rasmussen, which uses a stringent screen, polls incessantly and is therefore overrpresented when sites like pollster.com or RealClearPolitics take poll averages.)  But the well-known finding that Democrats had to be leading in the generic Congressional ballot to hold the house was based on past Gallup polls, which didn’t use a screen.  Democrats needed a big edge to overcome their historically lower turnout in midterm elections.  But likely voter screens, if they’re working as advertised, already control for lower Democratic turnout.

Pundits are routinely double-counting greater Republican enthusiasm.

Author: Andrew Sabl

Andrew Sabl, a political theorist, is Associate Professor of Political Science at the University of Toronto. He is the author of Ruling Passions: Political Offices and Democratic Ethics and Hume’s Politics: Coordination and Crisis in the History of England, both from Princeton University Press. His research interests include political ethics, liberal and democratic theory, toleration, the work of David Hume, and the realist school of contemporary political thought. He is currently finishing a book for Harvard University Press titled The Uses of Hypocrisy: An Essay on Toleration. He divides his time between Toronto and Brooklyn.