Our best tool for predicting midterm elections doesn’t show a Republican wave – but history is on the GOP’s side

Like every two years, control of the House and Senate will once again be in play in the midterm elections of November 2022, and one of the best tools we have for predicting the outcome of these elections is the ballot. generic Congress ballot. The generic congressional ballot question typically asks respondents which party they intend to vote for in the next congressional election, without naming specific candidates, allowing the question to be asked nationwide to gauge the vote. overall political environment. And for several years now, at FiveThirtyEight, we’ve been collecting these polls and calculating a weighted average for them, and today we’re excited to release our generic vote average for the 2022 election cycle.

As of Thursday, September 16, Democrats are ahead of Republicans in our poll average by 2.7 percentage points (43.8% to 41.1%). This average is calculated in much the same way as our presidential approval average, with a few differences. First, the lines we draw for the generic ballot averages are smoothed out more aggressively; in other words, they are slower to react to new data. (Because generic polls are less common than presidential approval polls, we found that in order to filter out noise, the generic poll average must incorporate a larger sample of polls that go further back in time than the average d presidential endorsement.) Second, while our presidential endorsement average prefers versions of polls that examine the broader universe (i.e. all adults vs. registered voters and registered voters vs. to probable voters), our generic poll average does the opposite. Indeed, while we want to know what all Americans think of the president, generic polls are fundamentally election polls – and we’re only interested in how actual voters will vote midway through.

Historically, a generic ballot average calculated in this way has been very good at predicting the national popular vote for the United States House. Using our poll database, we are able to calculate a retroactive generic poll average for Congressional elections going back to 1980. On average, over these 21 election cycles, our generic polling day average missed the popular vote in the House of just 3.0 points.

Yes, as you may recall, the generic polls misled in the 2020 election: They gave Democrats an average lead of 7.3 points on November 3, but the party did not win. the popular vote in the House only 3.0 points. But that was an unusually large polling error by recent historical standards. In fact, from 2008 to 2018, the average error of our retroactive generic polling day averages was only 1.3 points. So, apart from 2020, the latest generic ballot polls have been remarkably accurate in recent years.

Of course, that’s just an argument for paying attention to our generic poll average on November 8, 2022 – not necessarily today. But it turns out that early generic polls can also be predictive, if you know how to interpret them. Specifically, for the midterm elections, you have to take into account the party that holds the White House, as that party is naturally at a disadvantage in the midterm elections.

The table below compares our retroactive averages of the generic polls to September 16, the year before a midterm election, with the possible margin of popular vote in the House for the midterms of 1982-2018. This shows that the president’s party generally loses ground between this point in the cycle and the election itself.

More precisely, the average of the polls in the generic ballot of the previous September overestimates the voting margin of the presidential party by 3.5 points on average. It is the manifestation of one of the strictest rules in politics: the party that owns the White House almost always does poorly halfway through.

Of course, there were a few exceptions. Most notable is the 2002 cycle, when President George W. Bush’s Republicans fell 6.7 points behind in the first generic ballot polls, but ultimately won the popular House vote by 4.6 points. But that year was exceptional: a rallying effect around the flag following the September 11, 2001 attacks made Bush incredibly popular, and those good feelings have rubbed off on his party. The 2006 and 2018 cycles were also exceptions as the president’s party neither lost nor gained significant ground between polls and actual results; the first generic ballot polls nailed the final margin almost exactly. But during these two years, the first polls already pointed to a bad year for the president’s party, showing Bush’s and President Donald Trump’s Republicans down 8.0 and 8.3 points, respectively.

In years when the president’s party leads the average in generic polls in September before midterm, the party underperforms those polls by 9.3 points on average. And that’s, in a nutshell, why Democrats should be worried about the 2022 election despite their current lead on the generic ballot. So far, this cycle looks a lot like former President Barack Obama’s two midterms (2010 and 2014) for Democrats in that they lead the generic polls by a few points in September of l year preceding the elections. But over the course of those two years, Republicans eventually rose up to our generic voting average and won the election with flying colors.

So, if Republicans outperform their early polls to a similar degree to 2010 and 2014, they could win the popular vote in the House by 5 to 7 percentage points, which would most likely give them control of the House (and probably from the Senate too). , since almost everyone votes a direct ticket to the party these days). Of course it’s a big if; there has been a lot of variability in these historical trends, so a wide range of outcomes is still possible. But even if the Republicans improve their position only little bit – something that is likely to happen, if history is any guide – it would probably still be enough to overthrow the House, given that their control of the redistribution process in a plurality of states is likely to strengthen the advantage structural GOP in House races. Past trends aren’t always true, but the smart money, at this point, stays with the president’s party losing control of Congress next year.

Mary Radcliffe and Aaron Bycoffe contributed to the research.