> It’s telling that he uses MLB games, rather than Presidential elections, which are not covered at all in that article.
All the types of predictions 538 does are covered in the Brier skills chart on the overall summary; there’s detailed analysis covering each type of prediction (with further available breakdowns for subtypes available once you’ve gone into the type) available from the dropdown at the top of the page.
OK, I missed the dropdown at the top. There is not "detailed analysis" for Presidential elections, although I guess you mean that each state is a data point.
All that graph shows is that their "probability" is roughly in the ballpark with huge errors in the middle of the range, which is probably the swing states we care about most.
I'll suggest one concrete case where their probability of a candidate winning a 2-person race has some exact meaning:
*You'll pick a number randomly from 1 to 100. If it's less than or equal to candidate A's "probability" of winning, then you bet $10,000 on A. Otherwise you bet $10,000 on B* (we need to put real skin in the game)
Are you willing to abide by that rule? If not, you don't really believe the probability.
> There is not “detailed analysis” for Presidential elections
There is, in fact, detailed analysis for Presidential elections.
> although I guess you mean that each state is a data point.
No, each individual prediction of each of the 56 (enumerated upthread) distinct elections for one or more Presidential electors is a data point.
> Are you willing to abide by that rule? If not, you don’t really believe the probability.
Well, no, not being willing to abide by that rule means either not being rich enough that winning and losing $10,000 are roughly symmetric in utility or not being an SBF-style nutball and demanding a non-zero risk premium. As it turns out, I am in both categories.
what does this mean, "each individual prediction of each of the 56 (enumerated upthread) distinct elections"?
how many predictions are there for each election? does 538 issue more than one per election? Or how many data points are there?
as for the last paragraph: I guess you don't really believe in their probabilities, then, which was my whole point. I have no idea what you're talking about, re "non-zero risk premium."
> how many predictions are there for each election?
One for each batch (which may be as small as one) of data (polls specifically in the polls-only model) added to the data; each takes into account current and past polls, with time.-based decay in weighting, distance from the election, and other factors. This includes polls for other contests in the same cycle, because the models accounts for correlation between them.
> does 538 issue more than one per election?
Sometimes multiple in a day for an election (especially the Presidential general election.)
> Or how many data points are there?
Well the scale for the bubbles on the Presidential election night calibration plot runs from 30-300 per bucket, and there’s 21 buckets.
> I have no idea what you're talking about, re "non-zero risk premium."
If you don't understand risk premiums and the asymmetric utility of nontrivial quantities of money, you have really no business talking about when a bet is reasonable.
Not very well.
> It’s telling that he uses MLB games, rather than Presidential elections, which are not covered at all in that article.
All the types of predictions 538 does are covered in the Brier skills chart on the overall summary; there’s detailed analysis covering each type of prediction (with further available breakdowns for subtypes available once you’ve gone into the type) available from the dropdown at the top of the page.