The Senate race in Alaska is as important as any in the country. As we’ve described previously, Republicans can win a Senate majority by winning the race there along with those in five other deeply red states: Arkansas, Louisiana, Montana, South Dakota and West Virginia. But Alaska is probably the toughest “get” of the six for the GOP.
Unfortunately, Alaska has received very little polling — and just about every poll we do have from the state has been either an Internet poll, an automated poll or a partisan poll. The stronger pollsters seem to be avoiding the state — perhaps for good reason.
A new, partisan poll of Alaska came out over the weekend. The survey, conducted for Senate Majority PAC by Harstad Strategic Research, shows the Democratic incumbent Mark Begich leading his Republican opponent Dan Sullivan 45 percent to 40 percent. That contradicts the last two nonpartisan polls of the state, which had shown Sullivan ahead.
Senate Majority PAC’s goals are pretty clear; its mission is to “protect and expand the Democratic majority in the U.S. Senate.” Longtime readers will know that we’re not fans of partisan polls, which tend to be inaccurate and biased.
But defining a partisan poll can be tricky. Many pollsters release some polls on behalf of campaigns, while publishing other results under their own names. Some polls have ties to interest groups that aren’t well disclosed: For instance, the polling firm We Ask America is a subsidiary of the Illinois’ Manufacturers Association. Explicitly partisan blogs and websites have been commissioning more of their own polls in recent years (of course, many people would claim that traditional media outlets like Fox News and the New York Times have their own biases).
We’ve experimented a lot with different definitions of what constitutes a partisan poll over the years and decided we’re not inclined to play “poll police” in borderline cases. So since 2012, we’ve been excluding only polls conducted directly on behalf of campaigns or party groups like the Democratic Senatorial Campaign Committee and the Republican National Committee. Everything else gets included in the FiveThirtyEight model — including this weekend’s Alaska poll.
But the model has a defense mechanism: its house effects adjustment, which evaluates polls for signs of a partisan lean and adjusts them accordingly. In this case, the model detects a significant Democratic house effect in Harstad’s polls, and it treats the Alaska survey as showing the equivalent of a 1 or 2 percentage-point lead for Begich, instead of a 5-point advantage. The poll still helps Begich some — his chances of winning the race jumped from 31 percent to 38 percent — but not nearly as much as if a nonpartisan pollster had shown the same result.
But there’s another reason to be suspicious of the poll — and others that purport to show Begich ahead in Alaska. As other commentators have noted, Alaska is a hard state to poll accurately. What we haven’t seen remarked upon is how those misses have come in one direction, almost always overestimating the performance of Democrats.
The table below lists Alaska results from our pollster ratings database, which covers polls conducted in the last three weeks of campaigns since 1998. (We’ll be publicly releasing this database soon.) For each race, I’ve compared the polling average against the actual margin, excluding the 2010 Senate campaign where the top two finishers were both Republicans, Joe Miller and Sen. Lisa Murkowski (who ran as a write-in candidate after losing her primary).
In every single race, the polls have shown a Democratic bias. In 2008, for instance, Begich was favored by almost 10 percentage points in the polls against the Republican incumbent Ted Stevens, but won by barely more than a percentage point. Also that year, the polls favored the Democrat Ethan Berkowitz to win the state’s at-large House district from the Republican incumbent Don Young, but Young prevailed instead. In 2004, the polls had the Democrat Tony Knowles, the state’s former governor, tied in his race against Murkowski, but Murkowski won by three points. In 2010, the Republican gubernatorial candidate Sean Parnell by a margin much larger than the polls anticipated. On average since 1998, polls of Alaska have had a 7-point bias toward Democrats.
The FiveThirtyEight model does not account for this property, but it’s something to keep in mind as you peruse polls of the state. The model does, however, include a “state fundamentals” estimate for each state, based on factors like fundraising and state partisanship, and includes it along with the polls.
The state fundamentals estimate does not receive very much weight in the model — it represents only about 15 percent of the projection in Alaska, for example, and as little as 5 percent in some other key states with more abundant polling.
Still, it can be interesting to look at. In Alaska, while our adjusted polling average puts Sullivan ahead by just one percentage point, the fundamentals estimate has him as an 8- or 9-point favorite instead. That gap of about seven points is right in line with the historical Democratic bias in Alaska polls.
Overall — also accounting for new polls in Louisiana and Georgia — the FiveThirtyEight forecast is not much changed. It shows Republicans with a 58 percent chance of winning the Senate majority, down just slightly from 59 percent Friday.
Check out FiveThirtyEight’s latest Senate forecast.