prior probability

Via Wikipedia (footnotes omitted): “Double chess is a chess variant invented by Julian S. Grant Hayward in 1916. The game is played on a 12×16 chessboard with each player in control of two complete armies placed side-by-side. The rules were published in the January 1929 issue of British Chess Magazine.” (Hat tip: @pickover.)

According to this gated paper by Cher Li, an assistant professor of economics at Colorado State University, and Basit Zafar, a professor of economics at Arizona State University, “male students are 18.6 percent more likely than female students to receive favorable grade changes initiated by instructors.” Really? Alas, their paper is gated, so I have no way of assessing the reliability of their methods, but what I would like to know is this: who is more likely to ask for a grade change in the first place, males or females, and does this likelihood in turn depend on the gender of the instructor? More details here (ungated), via IHE. (Hat tip: @AgnesCallard.)

Via POLITICO: Each circle represents the difference in votes between the winner and the runner-up in each one of Iowa’s 99 counties. Larger circles indicate a larger gap between the first- and second-place candidates.

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What is a caucus, you ask? It is a highly interactive and time-consuming method of voting. According to this excellent step-by-step explanation by Dominico Montanaro (via NPR), here is what is supposed to happen in each of Iowa’s 1765 electoral precincts on caucus night:

1. First, there’s a call to order, and a caucus chairman (or chairwoman) and secretary are elected.
2. Next, supporters are allowed to make the case for their candidates. (Note: Does this argument stage proceed in alphabetical order, or is a random selection method used, e.g. slips of paper with each candidate’s name chosen out of a hat?)
3. Caucus-goers then separate into clusters in different parts of the room for their candidate of choice.
4. After the groups are formed, the caucus chairman adds up how many supporters are in each cluster.
5. Each candidate has to meet a “viability threshold” of 15%, i.e. the number of people in each cluster has to be at least 15% of the total number of participants in the room.
6. If a candidate does not meet this critical threshold, that candidate’s supporters must then choose another candidate. As a result, this viability threshold introduces an additional layer of uncertainty into the outcome of the caucus. By way of example, if Andrew Yang does not meet the threshold, are Yang supporters more likely to switch over to Bernie Sanders or to Liz Warren?
7. During this re-caucusing stage, supporters of the remaining viable candidates try to sway the nonviable candidate’s voters to their side.
8. Once this re-caucusing stage is completed and all remaining candidates are deemed viable, the votes are tallied.
9. At this point, delegates and alternates are selected to attend county conventions, and then platform resolutions are introduced.
10. Lastly, the caucus is adjourned.

If you are in the Orlando area, skip Disney and visit the Orlando Museum of Art instead. OMA is featuring a special exhibit on The Florida Highwaymen, a remarkable group of Afro-American painters from Ft Pierce, Florida who revolutionized the world of landscape painting.