Chess Tactics Server: Some Data
Originally posted 12/05I couldn't sleep, so I thought I'd do a little analysis of the data at the Chess Tactics Server (CTS). CTS has engendered more than a little interest amongst the Knights, especially in our intrepid Temposchlucker, whose mania in problem solving can only be described as insane. I got the data from all members who did more than 100 problems in the last month, and plotted rating versus number of problems solved. The scatter plot is here, where the x-axis is number of problems solved in the last month (on a logarithmic scale: most people have done a lot fewer than 1000 problems) and the y-axis is the rating:
The blue line is the best linear fit (slightly curved upward toward the right because of the logarithmic scale on the x-axis), the red dot is Tempo's rating, and the green dot is Jadoube's rating. Note that Tempo is right on the line: he is about at the average for people who have done ~5000 problems in the last month, while Jadoube is a bit below the line, as he is a bit below the average for people who have done ~2000 problems in the last month.
A couple of things to notice. The correlation coefficient of 0.09 is small but significant (p<.05), and the slope of the line is ~0.0132. Interpreting this is difficult, but it suggests that ratings are not strongly influenced by problem frequency. This is pretty clear by inspection of the data, which shows no clear upward trend. One possible interpretation is that for every thousand problems you do, you can expect to improve by 13 rating points. This is significantly higher than Tempo's fun estimate of 2.4 points/1000 problems which he hopes to gain in his training. On the other hand, interpreting such graphs is always problematic: it is likely that solving more problems is correlated with higher motivation to improve as well as other chess efforts which CTS doesn't measure. Remember, correlation does not equal causation: I could do 30000 problems in a month while watching TV, and have a rating of 10.
At any rate, I just geeked out during a bout of insomnia.