Month: December 2015

I’m checking the page proofs for an article that my student Haonan Liu and I have had accepted for publication in Physical Review D. I’ve worked with dozens of undergraduates on research projects over the years, and this is by far the most substantial work ever done by any of them. Huge congratulations to Haonan! (And to my friends on admissions committees for physics Ph.D. programs: look out for this guy’s application.)

Incidentally, we submitted this article before the Open Journal for Astrophysics opened its doors, so this isn’t the one I referred to in my last post. That one isn’t finished yet.

Along with the page proofs come a few comments and queries from the editors, to make sure that the published version of the article looks correct. That document says, in part,

The editors now encourage insertion of article titles in references to journal articles and e-prints.

If you’re not in physics or astronomy, this sentence probably seems strange: how could you possibly not include the titles of articles? If you do work in physics or astronomy, you’ve probably gotten used to the fact that we generally don’t give titles in citations, but this is an incredibly stupid thing. When you’re reading a paper, and you have to decide if it’s worth the bother of looking up a cited article, the title might actually be useful information! Other disciplines include titles. I’ve never understood why we don’t. Thank you to Physical Review for this bit of sanity.

Here’s what a bit of the bibliography originally looked like:

 

Now it’ll be

Much better!

Of course, the standard LaTeX styles used for formatting articles for publication in physics journals don’t include article titles, so including them at this stage actually took a bit of effort on my part, but I was glad to do it. I hope other journals follow this practice. Maybe I’ll mention it to someone on the board of the Open Journal.

I’m pleased to point out that the Open Journal of Astrophysics is now open for submissions. Editor-in-chief Peter Coles has all the details. I’m a member of the editorial board of this new journal, although I confess that I have done nothing to help with it so far.

The journal performs peer review like other scholarly journals. Articles in it are published on the arxiv (where most astrophysics articles get posted anyway). The journal does not have the overhead of publishing in the traditional way, so it is free for both authors and readers.

I find the economics of traditional scholarly journals utterly baffling. As Coles observes, “The only useful function that journals provide is peer review, and we in the research community do that (usually for free) anyway.” I hope that efforts like this one will point the way to a more efficient system. I urge my astrophysics colleagues to submit articles to it.

Now let me confess to a bit of hypocrisy, or at least timidity. I’m hoping to submit an article for publication in the next few weeks, and I’m planning to send it to an established journal, not the Open Journal. The only reason is that I expect to apply for promotion (from Associate Professor to Full Professor) this summer, and I think there’s a significant possibility that some of the people evaluating my application will be more impressed by an established journal, with all the various accoutrements such as impact factors that go along with it.

This is quite possibly the last time in my career that I’ll have to worry about this sort of thing. In general, I care about the opinions of people who have actually read my work and formed a judgment based on its merits. Such people don’t need to rely on things like impact factors, which are a terribly stupid way to evaluate quality. So after this one, I’ll promise to submit future articles to the Open Journal (unless I have coauthors whom I can’t persuade to do it, I guess).

 

When people talk about US politics, they often focus on the various candidates’ “electability”. In particular, they talk about basing their support for a given candidate in the primary on how likely that candidate is to win the election.

This is a perfectly reasonable thing to think about, of course. If your primary goal is, say, to get a Democrat into the White House, then it makes sense to pick the Democrat who’s most likely to get there, even if that’s not your favorite candidate. The only problem is that, I suspect, people are often quite bad at guessing who’s the most electable candidate.

Eight years ago, I observed (1,2,3) that there is one source of data that might help with this, namely the political futures markets. These are sites where bettors can place bets on the outcomes of the elections. The odds available on the market at any given time show the probabilities that the bettors are willing to assign to the various outcomes. For instance, as of yesterday, at the PredictIt market, you could place a bet of $88 that would pay off $100 if Hillary Clinton wins the Democratic nomination. This means that the market “thinks” Clinton has an 88% chance of getting the nomination.

To assess a candidate’s electability, you want the conditional probability that the candidate wins the election, if he or she wins the nomination. The futures markets don’t tell you those probabilities directly, but you can get them from the information they do give.

Here’s a fundamental law of probability:

P(X becomes President) = P(X is nominated) * P(X becomes President, given that X is nominated).

The last term, the conditional probability, is the candidate’s “electability”. PredictIt lets you bet on whether a candidate will win the nomination, and on whether a candidate will win the general election. The odds for those bets tell you the other two probabilities in that equation, so you can get the electability simply by dividing one by the other.

So, as of Saturday, December 5, here’s what the PredictIt investors think about the various candidates:

Party	Candidate	Nomination Probability	Election Probability	Electability
Democrat	Clinton	88.5	57.5	65
Democrat	Sanders	12.5	6.5	52
Republican	Bush	9.5	4.5	47
Republican	Cruz	25.5	10.5	41
Republican	Rubio	39.5	19.5	49
Republican	Trump	25.5	15.5	61

(In case you’re wondering, the 0.5’s are because PredictIt has a 1% difference between the buy and sell prices on all these contracts. I went with the average of the two. They include other candidates, with lower probabilities, but I didn’t include them in this table.)

I’ve heard lots of people on the left say that they hope Donald Trump wins the nomination, because he’s unelectable — that is, the Democrat would surely beat him in the general election. I don’t know if that’s true or not, but it’s sure not what this market is saying.

Of course, the market could be wrong. If you think it is, then you have a chance to make some money. In particular, if you do think that Trump is unelectable, you can go place a bet against him to win the general election.

To be more specific, suppose that you are confident the market has overestimated Trump’s electability. That means that they’re either overestimating his odds of winning the general election, or they’re underestimating his odds of getting the nomination. If you think you know which is wrong, then you can bet accordingly. If you’re not sure which of those two is wrong, you can place a pair of bets: one that he’ll lose the general election, and one that he’ll win the nomination. Choose the amounts to hedge your bet, so that you break even if he doesn’t get the nomination. This amounts to a direct bet on Trump’s electability. If you’re right that his electability is less than 61%, then this bet will be at favorable odds.

So to all my lefty friends who say they hope Trump wins the nomination, so that Clinton (or Sanders) will stroll into the White House, I say put your money where your mouth is.