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
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