Students of econometrics who want to learn concepts more deeply are often confronted by the need to know some abstract linear algebra. This is especially the case in econometrics courses that emphasize the mathematical properties of ordinary least squares.

Economic research requires writing documents, and often writing code. How can economists avoid drowning in a mess of different versions? How can they keep everything organized, and keep track of the changes they made? How can coauthors work constructively on the same set of files without going crazy?

I prepared some notes on demand estimation in industrial organization that survey a selected set of discrete choice models, from multinomial logit to modern Berry, Levinsohn, and Pakes-type methods.

Expect more soon.