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538: How Our 2022 Midterm Forecasts Performed
Let’s get this out of the way up front: There was a wide gap between the perception of how well polls and data-driven forecasts did in 2022 and the reality of how they did … and the reality is that they did pretty well.
While some polling firms badly missed the mark, in the aggregate the polls had one of their most accurate cycles in recent history. As a result, FiveThirtyEight’s forecasts had a pretty good year, too. Media proclamations of a “red wave” occurred largely despite polls that showed a close race for the U.S. Senate and a close generic congressional ballot. It was the pundits who made the red wave narrative, not the data.
With that said, the polls weren’t perfect.
- Polling averages and forecasts did slightly underestimate Democrats, though the differences were modest — certainly less than the extent to which they underestimated Republicans in 2016 and 2020.
- Some pollsters — such as Trafalgar Group and Rasmussen Reports, which have a history of Republican-leaning polling — had a conspicuously poor year.
- There are different methods of polling aggregation and forecasting. The margins in the polling averages from RealClearPolitics were on average 1.3 percentage points more favorable to Republicans in the most competitive Senate races1 than those published by FiveThirtyEight. Similarly, RCP’s generic ballot polling average was 1.3 points more favorable to the GOP than FiveThirtyEight’s. In this article, I’ll only be evaluating FiveThirtyEight’s forecasts, but methodological choices made a difference.
- Finally, Democrats’ relatively strong year — although there were some precedents for it — defied a lot of midterm history. It’s not just that the polls did better than the conventional wisdom; they also did well relative to political science or “fundamentals”-based forecasting methods.
So let’s dig into the FiveThirtyEight forecast. As you may know if you follow our work closely, we publish three different versions of our congressional and gubernatorial forecasts. Version one is a Lite forecast that sticks as much as possible to the polls themselves. (In races that have little polling, Lite makes inferences from the generic ballot and from polls of other races.) Our Classic forecast blends the polls with other data — for instance, information on candidate fundraising, incumbency and the voting history of the state or district. Finally, our Deluxe forecast adds in another layer, namely race ratings from outside groups such as The Cook Political Report. Deluxe is the default when you pull up our forecast interactive and the version that we use most often when describing our forecasts.
https://fivethirtyeight.com/features/how-our-2022-midterm-forecasts-performed/
While some polling firms badly missed the mark, in the aggregate the polls had one of their most accurate cycles in recent history. As a result, FiveThirtyEight’s forecasts had a pretty good year, too. Media proclamations of a “red wave” occurred largely despite polls that showed a close race for the U.S. Senate and a close generic congressional ballot. It was the pundits who made the red wave narrative, not the data.
With that said, the polls weren’t perfect.
- Polling averages and forecasts did slightly underestimate Democrats, though the differences were modest — certainly less than the extent to which they underestimated Republicans in 2016 and 2020.
- Some pollsters — such as Trafalgar Group and Rasmussen Reports, which have a history of Republican-leaning polling — had a conspicuously poor year.
- There are different methods of polling aggregation and forecasting. The margins in the polling averages from RealClearPolitics were on average 1.3 percentage points more favorable to Republicans in the most competitive Senate races1 than those published by FiveThirtyEight. Similarly, RCP’s generic ballot polling average was 1.3 points more favorable to the GOP than FiveThirtyEight’s. In this article, I’ll only be evaluating FiveThirtyEight’s forecasts, but methodological choices made a difference.
- Finally, Democrats’ relatively strong year — although there were some precedents for it — defied a lot of midterm history. It’s not just that the polls did better than the conventional wisdom; they also did well relative to political science or “fundamentals”-based forecasting methods.
So let’s dig into the FiveThirtyEight forecast. As you may know if you follow our work closely, we publish three different versions of our congressional and gubernatorial forecasts. Version one is a Lite forecast that sticks as much as possible to the polls themselves. (In races that have little polling, Lite makes inferences from the generic ballot and from polls of other races.) Our Classic forecast blends the polls with other data — for instance, information on candidate fundraising, incumbency and the voting history of the state or district. Finally, our Deluxe forecast adds in another layer, namely race ratings from outside groups such as The Cook Political Report. Deluxe is the default when you pull up our forecast interactive and the version that we use most often when describing our forecasts.
https://fivethirtyeight.com/features/how-our-2022-midterm-forecasts-performed/
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