Here are the final numbers I will publish before the election. Some more surveys might come in between now and when the polls close, but the update with those polls will only appear in the final analysis of how well the methodology worked (or didn’t work).
Senate Campaigns Chart
Margins are based on the simple average of all published polls (except Zogby Interactive and Columbus Dispatch) in which the majority of interviews were conducted on or after October 8th. I do not forecast the outcomes of campaigns where the final polling average is greater than 18.5%. All polls used in the averages are taken from Pollster.com and Real Clear Politics. Click here for the Senate Snapshot methodology.
Senate seat outcome odds chart
Even though Democrats only lead in 51 seats, narrow Republican leads in Illinois, Colorado and Nevada makes 52 Democratic seats the most likely outcome. As such, 52 Democratic seats is my final prediction. Here are the specific odds for each possible outcome:
55 seats: 0.5%
54 seats: 4.3%
53 seats: 17.1%
52 seats: 33.8%
51 seats: 31.1%
50 seats: 11.3%
49 seats: 1.7%
48 seats: 0.1%
Polling averages are treated as independent variables, an idea which I know not everyone accepts.
Governor Campaigns Chart
--I’m taking a mulligan in the Alaska Senate campaign. Murkowski’s write-in candidacy makes polling unusually difficult. Please don’t judge me on the outcome of that campaign. No matter what happens, I’m not including it in my database once the election is over.
--We won’t have final vote totals everywhere until mid-December (and possibly later). When that time comes, I will compare the accuracy of my methodology to Five Thirty Eight, Pollster.com, and Real Clear Politics. But really, all of our predictions are pretty much the same. The difference in the average accuracy of our predictions will only be a few tenths of a percent.
--Above all else, don't let these projections get you down. They are just odds based on available information. Some of the realistic outcomes projected here, such as 54 Senate seats, are not that bad. Also, as Steve showed earlier today, a 2-3% across the board swing in favor of Dems, and we even might keep the House. Check out Nate Silver's piece on how "Democrats Could Beat the Polls and Hold the House," too. And if every forecaster is proven wrong, well, this wouldn't be the first election when that happened.
Keep your chin up, and vote. It's not over until the polls close.