Notably, the 538 prediction doesn’t include a number of outside factors, primarily around mail-in ballots and voter suppression. 538 has already talked about the problems with mail-in ballots being rejected, and there are also concerns about not having all of the ballots counted before the cut-off point where they have to finish counting. Republicans have also made it harder for Democrat-leaning bases to vote. These are factors that will hurt Biden more than Trump. All those links are to 538, and there are other articles on the site about those same issues. If you believe in 538′s model, you should probably also believe in their articles that indicate that these outside factors will be important. If you don’t believe in the articles, then why do you believe in their model?
Either way, this is not a clear case where the market is wrong.
Only the first article in the comment is by Silver, on whose expertise the original poster is basing his recommendation. That article doesn’t discuss mail-in ballots or voter suppression, and in fact his main point is that the time remaining until election day (almost three months when the article was written) combined with uncertainties due to Covid-19 meant that the race was still open back then. Those considerations have much more limited force at present, when only 16 days remain, and Biden’s lead has widened considerably.
If you’ve been at all listening to Silver recently, you’ll know that he thinks his model probably underestimates Biden’s chances. This shouldn’t be surprising, since as Silver acknowledges, in this new version of the model he has made a special effort to build conservative assumptions into it.
In any case, I would encourage people hesitant to bet for Biden to resist the temptation of “throwing in a bunch of considerations” for why the models may be wrong, and instead try to calculate what the correct forecast should be in light of those considerations. For example, if you think mail-in ballots will be a big factor, try to estimate the magnitude of this effect.
Following my own advice, I just built a simple Guesstimate model of the impact of mail voting on the popular vote. I created the model very quickly, so if anyone spots any errors, please mention them below. And if you think some of the parameters should be different, simply copy the model and adjust those parameters to your satisfaction. Note that the effect of “rejected” in-person ballots is not modeled. This effect favors Biden, since a greater proportion of Trump votes will be in person, and hence susceptible to being “rejected” (i.e., not cast due to failure to bring an ID, long lines, inability to find a polling station, etc).
ETA: The upshot of the model is that mail voting shrinks the expect popular vote gap between Biden and Trump by about 2%. If we assume that the electoral college gives Trump a ~2% popular vote advantage, the model implies a drop in Biden’s chances of winning the election from 87% to about 79%. [I modified the model and improved some of the estimates, and now the effect is less than 1%.]
(Disclosure: I have bet a total of USD 12k on Biden, mostly back when his odds where roughly equal with Trump’s.)
This model seems reasonable, but I think bettors should mostly ignore the possibility of rejected mail in ballots, because the effect is extremely uncertain and around the same magnitude as many other idiosyncratic factors that should mostly wash out. For example, if there’s severe weather or an outbreak of COVID on election day in a crucial swing state, that will hurt Trump much more than Biden because a much greater proportion of his voters are voting by mail (essentially the “rejected in person ballots” effect you mention).
The 538 distribution currently has Biden falling between… <squints> ~255 − 440 electoral votes 80% of the time (47% − 82%). Updating your guesstimate sheet with those ranges give a mean proportion to Trump of .38 with a range of .17 − 0.54
This is total misinformation; mail-in rejection will probably be cancelled out by increased turnout from low-propensity voters (it’s much easier to vote by mail than to vote in person). In any case, the effect of a 1-3% rejection rate is minimal and indistinguishable from general noise/uncertainty.
Most of the claimed “GOP voter suppresion” either has a minimal effect or hurts the GOP, because the nuts and bolts of election administration are implemented on a county level. In most states, urban counties have the resources and inclination to counter the voter suppression, while rural (predominantly GOP) counties do not.
I was merely noting that 538, the makers of the prediction model that the post is discussing, believes in the voter suppression. If you think they’re wrong about the voter suppression, then you probably also shouldn’t believe in their prediction model. On the other hand, if you think they’re right about the prediction model, then why are you doubting their voter suppression research?
Of course, it’s perfectly consistent to think that they are wrong about both the model and the voter suppression, but the post was assuming that you believed in the prediction model.
Notably, the 538 prediction doesn’t include a number of outside factors, primarily around mail-in ballots and voter suppression. 538 has already talked about the problems with mail-in ballots being rejected, and there are also concerns about not having all of the ballots counted before the cut-off point where they have to finish counting. Republicans have also made it harder for Democrat-leaning bases to vote. These are factors that will hurt Biden more than Trump. All those links are to 538, and there are other articles on the site about those same issues. If you believe in 538′s model, you should probably also believe in their articles that indicate that these outside factors will be important. If you don’t believe in the articles, then why do you believe in their model?
Either way, this is not a clear case where the market is wrong.
Only the first article in the comment is by Silver, on whose expertise the original poster is basing his recommendation. That article doesn’t discuss mail-in ballots or voter suppression, and in fact his main point is that the time remaining until election day (almost three months when the article was written) combined with uncertainties due to Covid-19 meant that the race was still open back then. Those considerations have much more limited force at present, when only 16 days remain, and Biden’s lead has widened considerably.
If you’ve been at all listening to Silver recently, you’ll know that he thinks his model probably underestimates Biden’s chances. This shouldn’t be surprising, since as Silver acknowledges, in this new version of the model he has made a special effort to build conservative assumptions into it.
In any case, I would encourage people hesitant to bet for Biden to resist the temptation of “throwing in a bunch of considerations” for why the models may be wrong, and instead try to calculate what the correct forecast should be in light of those considerations. For example, if you think mail-in ballots will be a big factor, try to estimate the magnitude of this effect.
Following my own advice, I just built a simple Guesstimate model of the impact of mail voting on the popular vote. I created the model very quickly, so if anyone spots any errors, please mention them below. And if you think some of the parameters should be different, simply copy the model and adjust those parameters to your satisfaction. Note that the effect of “rejected” in-person ballots is not modeled. This effect favors Biden, since a greater proportion of Trump votes will be in person, and hence susceptible to being “rejected” (i.e., not cast due to failure to bring an ID, long lines, inability to find a polling station, etc).
ETA:
The upshot of the model is that mail voting shrinks the expect popular vote gap between Biden and Trump by about 2%. If we assume that the electoral college gives Trump a ~2% popular vote advantage, the model implies a drop in Biden’s chances of winning the election from 87% to about 79%. [I modified the model and improved some of the estimates, and now the effect is less than 1%.](Disclosure: I have bet a total of USD 12k on Biden, mostly back when his odds where roughly equal with Trump’s.)
This model seems reasonable, but I think bettors should mostly ignore the possibility of rejected mail in ballots, because the effect is extremely uncertain and around the same magnitude as many other idiosyncratic factors that should mostly wash out. For example, if there’s severe weather or an outbreak of COVID on election day in a crucial swing state, that will hurt Trump much more than Biden because a much greater proportion of his voters are voting by mail (essentially the “rejected in person ballots” effect you mention).
The 538 distribution currently has Biden falling between… <squints> ~255 − 440 electoral votes 80% of the time (47% − 82%). Updating your guesstimate sheet with those ranges give a mean proportion to Trump of .38 with a range of .17 − 0.54
This is total misinformation; mail-in rejection will probably be cancelled out by increased turnout from low-propensity voters (it’s much easier to vote by mail than to vote in person). In any case, the effect of a 1-3% rejection rate is minimal and indistinguishable from general noise/uncertainty.
Most of the claimed “GOP voter suppresion” either has a minimal effect or hurts the GOP, because the nuts and bolts of election administration are implemented on a county level. In most states, urban counties have the resources and inclination to counter the voter suppression, while rural (predominantly GOP) counties do not.
I was merely noting that 538, the makers of the prediction model that the post is discussing, believes in the voter suppression. If you think they’re wrong about the voter suppression, then you probably also shouldn’t believe in their prediction model. On the other hand, if you think they’re right about the prediction model, then why are you doubting their voter suppression research?
Of course, it’s perfectly consistent to think that they are wrong about both the model and the voter suppression, but the post was assuming that you believed in the prediction model.