Everyone treats them as pronouncements from on high, but this year pre-election polls are especially questionable. This year, I believe the polls will be especially unrealiable. A quick review of RealClearPolitics.com illustrates the problem. On October 22nd, a CBS News/NY Times polls shows Senator Barack Obama leading Senator John McCain by 13 percentage points. Rasmussen Reports reports the lead is seven percent. Gallup offers two polls: a “traditional” poll showing a four percent lead and an “expanded” one showing a six percent lead. Reuters/C-Span/Zogby has Senator Obama ahead by 12 percent and Hotline/FD shows him leading by just five percent.
How can six polls released on the same day have such disparite results? It’s one thing for polls to be unreliable predictors of what will happen on election day. It’s another to be all over the map on the same day. What’s going on here?
Alan Fram of the Associated Press provides some answers in an article well worth reading. The all news stations have to talk about something and poll results are a favorite topic. After all, it has numbers. You have one person winning and another losing. It’s a heck of a lot simpler to cover than tax policy.
So, since you’re going to be hearing and reading a lot about polls from now until November 4th, you might as well understand why every poll should be read with vast quantities of salt. It doesn’t make them any more reliable, but it does help them taste better.