Gilgamath

I have become more interested in chess in the last year, though I'm still pretty much crap at it. Rather than play games, I am practicing tactics at chesstempo. Basically you are presented with a chess puzzle, which is selected based on your estimated tactical 'Elo' rating, and your rating (and the puzzle's) is adjusted based on whether you solve it correctly. (Without time limit for standard problems, though I believe one can also train in 'blitz' mode.) I decided to look at the data.

I have a few reasons for this exercise:

1. To see if I could do it. You cannot easily download your stats from the site unless pay for gold membership. (I skimped and bought a silver.) I wanted to practice my web scraping skills, which I have not exercised in a while.
2. To see if the site's rating system made sense as a logistic regression, and were consistent with the 'standard' definition of Elo rating.
3. To see if I was getting better.
4. To see if there was anything simple I could do to improve, like take longer for problems, or practice certain kinds of problems.
5. To look for 'hot hands' phenomenon, which would translate into autocorrelated residuals.

The bad and the ugly

Scraping my statistics into a CSV turned out to be fairly straightforward. The statistics page will look uninteresting if you are not a member. Even if you are, the data themselves are served via JavaScript, not in raw HTML. While this could in theory be solved via, say, phantomJS, I opted to work with the developer console in Chrome directly.

First go to your statistics page in Chrome. Then conjure the developer console by pressing <CTRL>-<SHIFT>-I. A frame should appear. Click on the 'Console' tab, then type in it: copy(document.body …