As the midterm elections approached, the New York Times undertook an interesting experiment: it conducted opinion polls in dozens of home districts and showed the results in real time. Together with the Siena College polling team, the idea was that users would get a better understanding of how poll results depend on voting models and the number of respondents by presenting the survey in a sort of election night, watch-the-results-unfold format.
At the same time, the team also generated a lot of survey results in districts that are important for the control of the house. A tons of results. There were 90 separate House polls, including nearly 30 districts that were questioned twice.
The results? Well, just a little bit everywhere, as you would expect if you visit a diverse set of home districts.
Forty of the polls had a Republican in charge. Forty-one had a democrat as leader. Five were tied up.
But there is a more interesting way to look at these results: they compare with what can be expected in each district, given the way the district voted in 2016. If we do that, the graph looks like this.
Here the pattern is a bit different: 59 districts were more Democratic than the 2016 vote, while 30 districts were more republican in the house than in 2016. (If we compare it with 2012, the difference is about the same.)
If we go a level deeper, it becomes even more interesting. If we put a simple trend line on those results, we see that the shift from 2016 became a little friendlier for the Republicans in early October, and then went back to the Democrats at the end of the polling. That first period overlaps with the struggle for the appointment of Brett M. Kavanaugh at the Supreme Court.
Patrick Ruffini from the data center Echelon Insights came to a similar realization in a different way. He compared the daily reactions in the Times poll with the first ten-day polls, finding that the republicans did much better at the beginning of October than at the end of September. By the end of the month, the pendulum had been folded back to the Democrats.
We can get a similar idea of how the polling changed over time by looking at those races that the Times had polled several times.
These are the races in which the Republicans improved in polling between the first and second Times-Siena poll. In seven of the 10 races the Republican ended with a lead; in four of those races they had walked around for the first time.
Here are the races that became friendlier for the Democrats.
Nineteen races became kinder to the Democrat in the course of the Times' polls. Fourteen of them ended with the democrat leadership; six of those 14 switched from a Republican lead to a Democratic one.
If you are curious how much this tells us about the Democrats who are retaking the House, do not pay attention to the fact that the results themselves are divided. Focus instead on the fact that these were almost all districts that were most recently held by Republicans.