Echoing a point I've been making for years, a Wall Street Journal story on the inexact science of campaign polling points out an array of challenges.
Opinion polls themselves had been getting harder to conduct long before the matchup between President George W. Bush and his Democratic rival, Massachusetts Sen. John Kerry. The reasons range from growing reluctance to participate in surveys to increasing reliance on cellphones rather than the land lines pollsters have long used to ensure demographic and geographic balance in surveys.
But this year's bitter presidential contest has heaped on new challenges. They include an exceptionally close race and a polarized electorate that magnifies the consequence of different polling methods. In addition, unprecedented voter-mobilization drives by both parties make it especially tough for pollsters to say which voters probably will show up on Election Day.
With a recent Pew survey showing Bush and Kerry in a statistical dead heat, a Gallup Poll gave the incumbent a lead of 13 percentage points.
The Journal does point out a potential benefit from the errancy of polls:
The approach plays on the so-called bandwagon effects that energize supporters of a surging candidate and dispirit those of a lagging one.
So, essentially polls are representative only of those who are surveyed in other words, worthless, except to those who can spin them properly.