Election models megathread

[kwabbit]

The senate model is clearly underestimating Republicans due to reliance on polls, the GOP has outperformed what the polls said in the Senate 4 cycles in a row, 2014, 2016, 2018 and 2020, in all 4 cycles the GOP won more senate seats than most projected, no reason to believe the polls have corrected for the bias.

I know that’s true for 3 of the elections, but are you sure about 2018? I thought the results matched the polls in the Senate then - it was only Democrat hopium that was defeated.

The finial 2018 FL Senate rcp average was was Nelson+2.4
The final rcp average for Indiana Senate 2018 was Donnelly +1.3, Braun won by 6

Now do the other races that year for comparison.

I believe polls also underestimated Rs in Ohio, Michigan, and Tennessee. Democrats were underestimated in Texas, Nevada, Arizona. Overall a small bias which overrated Democrats, but it was more of an issue of underrating the partisanship of red states.

[kwabbit]

The senate model is clearly underestimating Republicans due to reliance on polls, the GOP has outperformed what the polls said in the Senate 4 cycles in a row, 2014, 2016, 2018 and 2020, in all 4 cycles the GOP won more senate seats than most projected, no reason to believe the polls have corrected for the bias.

I know that’s true for 3 of the elections, but are you sure about 2018? I thought the results matched the polls in the Senate then - it was only Democrat hopium that was defeated.

The finial 2018 FL Senate rcp average was was Nelson+2.4
The final rcp average for Indiana Senate 2018 was Donnelly +1.3, Braun won by 6

Now do the other races that year for comparison.

There’s a lot of reason to believe that polls are once again underestimating Republicans. The most significant is that pollsters have made few changes to methodology to prevent a repeat of the error that happened in 2020. At least after 2016, pollsters were vocal about now weighting for education.

After 2014, 2016, and 2020 were all significant misses, with only 2018 being accurate, it’s reasonable for one’s prior to be that polls will underestimate Republicans. Not that it’ll be a miss as strong as 2020, but it’s likelier than not for the polls to miss in that direction.

[kwabbit]

Dems went from 65 to 67 in 538 Senate and 29 to 30 in the House? Any ideas what caused this? No polling that came out today was divergent enough or high rated enough to cause such a change. Maybe their fundamentals model incorporated some news.

[kwabbit]

I'm really confused about how 538's model is working.  Siena releases 4 polls this morning showing Dems doing better than expected in every race.  Siena is an A+ rated pollster on 538, in fact the only A or A+ rater pollster polling any of these races as far as I can tell.

And these polls don't move the needle the slightest bit today any of these races.  What is 538 basing these predictions on if not these sort of polls?  (I know there's generic ballots and fundamentals and stuff, but shouldn't they be relying on this at least a little?)

It did help the Dems, it’s just that the other polls today hurt them. The NYT polls also aren’t super fresh, they’re already a bit old. NV had no effect, the AZ poll helped Kelly but the other polls today hurt him, the PA poll helped Fetterman, and the poll helped Warnock but the AJC poll balanced it out. I think the model calculates a house effect in PA and AZ that limited the effect, but not in GA or NV where NYT polls haven’t over estimated Democrats as much.