Remember: Exit Polls Even More Innacurate and Biased Than Opinion Polls

Tomorrow is election day. With a election day comes a special variety of polls--exit polls. Remember and let your friends know loud and clear. When it comes to bias and inaccuracies exit polls are far worse than opinion polling. Given the horrific state of opinion polling, that is a strong statement.

Drudge Report is publishing a McCain camp memo on the historical problems with exit polls.

Here are the key points to keep in mind when the exit poll data starts being leaked:

1. Historically, exit polls have tended to overstate the Democratic vote.

2. The exit polls are likely to overstate the Obama vote because Obama voters are more likely to participate in the exit poll.

3. The exit polls have tended to skew most Democratic in years where there is high turnout and high vote interest like in 1992 and 2004.

4. It is not just the national exit poll that skews Democratic, but each of the state exit polls also suffers from the same Democratic leanings.

5. The results of the exit polls are also influenced by the demographics of the voters who conduct the exit polls.

This is all spot on. You can rest assured that come 9:30am EST tomorrow, some exit polling data will be leaked despite the fact that it violates campaign laws. The exit polling will almost assuredly suggest that Obama is up by 20 points, the EVERY battleground state is going to Obama and that landslide is in full effect. Don't believe it. Don't let your friends believe it. Don't let misinformation deprive you of your one vote.

The memo also notes:

After the 2004 election, the National Election Pool completed a study investigating why the exit polls that year showed John Kerry over performing 5.5 net points better than the actual results showed him to have done. Their conclusion was that the primary reason the exit polls was that Kerry voters and Democrats were more likely to participate in the exit polls.

“Our investigation of the differences between the exit poll estimates and the actual vote count point to one primary reason: in a number of precincts a higher than average Within Precinct Error most likely due to Kerry voters participating in the exit polls at a higher rate than Bush voters. There has been partisan overstatements in previous elections, more often overstating the Democrat, but occasionally overstating the Republican.

Finally Steve Schippert at Wizbang adds one more point to the memo:

6. Exit Polls are not taken at every polling location, and tend to center around large cities, which are already more heavily Democrat than Republican.

This is a very important point. At least with opinion polling, agencies can call people in different regions of the state with different socioeconomic conditions. It is impossible for them to station exit pollsters at every polling location. (For example, my brother lives in rural Ohio and his polling location is a building the state stores salt and snow plows in. It is unlikely that CNN is going to have Cooper stationed there.) It is much more likely for them to be asking questions outside urban locations. But we all know what sort of bias this produces.

The point above still stands and is the major takeaway point. Vote. Ignore leaked exit polls and vote.