For my next experiment, I used Jeff Coakley’s Winning Chess Exercises for Kids. The main part of this book has 900 problems, with nine to a page. I divided these problems into ten batches. The first batch was pages 1, 11, 21..., and he second batch was pages 2, 12, 22..., and so on. My schedule was:

Sa Mo Fr Fr We

Week 1: A1, A2, A3 Days: 1-7

Week 2: B1, B2, B3, A4 Days: 8-14

Week 3: C1, C2, C3, B4 Days: 15-21

Week 4: D1, D2, D3, C4, A5 Days: 22-28

Week 5: E1, E2, E3, D4, B5 Days: 29-35

Week 6: F1, F2, F3, E4, C5 Days: 36-42

Week 7: G1, G2, G3, F4, D5 Days: 43-49

Week 8: H1, H2, H3, G4, E5 Days: 50-56

Week 9: I1, I2, I3, H4, F5, A6 Days: 57-63

Week 10: J1, J2, J3, I4, G5, B6 Days: 64-70

Where A1, A2, A3.… are passes 1, 2, 3... of batch A, and similarly for the other batches. Passes 1 to 5 were spaced at the same intervals as in the previous two experiments, but I delayed Pass 6 for a week. I modified the Empirical Rabbit Timer to cope with problems occurring in clumps (pages in this case). Incorrect solution times were counted as more than 60 seconds irrespective of the actual time spent. I stopped the clock as soon as I thought that I had found the solution, and counted my solution as correct if I got the right idea and the right first move. Here is a comparison of my performance aggregated over the first passes through all ten batches with the corresponding results from the Susan Polgar and Ivaschenko 1b Experiments:

￼

Coakley appears to be at a similar level of difficulty overall as Stage 5 of Ivashchenko (but the range of difficulty in Coakley is wider). Here is a chart for my first pass through each of the problem batches:

￼

There is no clear evidence of improvement here. Any improvement that I did make has been swamped by the random variation in the results. The time limit method described in my earlier article Rating Points Revisited gives the table:

Sec Gain SD Gain/SD

0-5 67 59 1.14

0-10 17 38 0.44

0-15 32 50 0.65

0-20 10 43 0.24

0-25 16 39 0.41

0-30 39 35 1.11

0-40 38 35 1.08

0-50 23 43 0.53

0-60 23 43 0.53

It is possible that I made a worthwhile improvement, but any improvement is about one standard deviation at best, so we cannot draw any reliable conclusions.

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