Reporting polling results as first differences

Please, pollsters: just tell us what’s changed from four years ago.

We know how the 2000 Presidential race came out: it was close. Nothing has happened in the meantime to radically redraw the map. So the obvious way to handicap this year’s election is to assume that each party starts out with what it had last year, and ask about changes. For some reason, none of the polls I’ve seen have been reported that way, until the latest Zogby effort:

Mr. Kerry is showing a 2-to-1 lead (50% to 25%) amongst voters who didn’t vote in 2000, while winning three-quarters (75%) of Ralph Nader’s voters and stealing twice as many (8% to 4%) of Mr. Bush voters in 2000 than Bush is stealing of Gore voters in 2000.

That, plus some sort of effort to estimate the sizes of the various groups (and of the Bush/Gore vote among those who have died in the interim) ought to provide a reasonable guess about the outcome.

Of course, since this is an immediately post-Convention poll, you can’t take the current encouraging numbers too seriously. But my point is about method; I’d like to see all the pollsters report results in this format from here on out.

Author: Mark Kleiman

Professor of Public Policy at the NYU Marron Institute for Urban Management and editor of the Journal of Drug Policy Analysis. Teaches about the methods of policy analysis about drug abuse control and crime control policy, working out the implications of two principles: that swift and certain sanctions don't have to be severe to be effective, and that well-designed threats usually don't have to be carried out. Books: Drugs and Drug Policy: What Everyone Needs to Know (with Jonathan Caulkins and Angela Hawken) When Brute Force Fails: How to Have Less Crime and Less Punishment (Princeton, 2009; named one of the "books of the year" by The Economist Against Excess: Drug Policy for Results (Basic, 1993) Marijuana: Costs of Abuse, Costs of Control (Greenwood, 1989) UCLA Homepage Curriculum Vitae Contact: