From link: * Using a slower-moving generic ballot average And a lower-degree polynomial -
one that uses a larger number of polls even if those polls are less recent — would have done a better job of maximizing predictive accuracy and minimizing autocorrelation in past years, so that’s what we used for the House model. And as of today, we’ve changed our generic ballot interactive to match the settings that our House model is using. Or at least, the versions will
almost match. The version in our House model uses a more complicated house effects adjustment, which, among other things,
incorporates data from congressional races in estimating pollsters’ partisan leans. It also
adjusts polls of registered voters and all adults to a likely-voter basis. But the differences that result are fairly minor. The average is designed to be slightly more aggressive as we approach Election Day, but in general, it will yield a much more stable estimate of the generic ballot than the one we’d been using before. We’ve also revised our generic ballot estimates for previous dates to reflect what they would have been using our new-and-improved methodology.
You can see that the new average takes more convincing before jumping at a new trend. (The generic ballot numbers as originally published will still be available — you can see them using the link under the chart.)
As an aside, this is one of the reasons that averaging polls isn’t quite as straightforward as it might seem.
How to manage the trade-off between using the most recent polls on the one hand and a larger sample of polls on the other hand is a tricky question and one where the right answer can vary between different types of elections.
For the generic ballot, you should take a rather conservative approach. But that doesn’t necessarily hold for something like a presidential race —
being too conservative would have caused you to miss crucial late movement toward Trump in 2016.
Why do you D hacks bother posting supposed "new polls" when said polls are actually based on old polls and specifically, and intentionally, do not reflect /current/ trending?
Or do ya'll just not read that fine print stuff?
