some cyber-dojo measurements

cyber-dojo has hosted about 13,000 practice sessions so far. I've written a short ruby script to extract some measurements from a sample of 500 sessions. I was looking at transitions between red, amber, and green traffic-lights:

• red means one or more tests failed
• amber means the tests did not run (eg syntax error)
• green means the tests ran and all passed

The first column is average number of lines added/deleted.
The second column is colour → colour transition.
The third column is sample size.

3.94	amber → green	447
4.65	amber → red	379
4.67	amber → amber	1462
5.39	red → green	607
6.01	red → red	604
7.52	green → red	420
13.65	green → amber	436
17.67	red → amber	432
22.18	green → green	598

Here's how I interpret the results:

• If you're at red or green and you make a small change (5.39,6.01,7.52) you're likely to stay at red or green.
• If you're at red or green and you make a large change (13.65,17.67) you're likely to transition to amber.
• There is a big spike in the number of amber → amber transitions (1462). I speculate that long sequences of these transitions are occuring after a large 13.65 green → amber or 17.67 red → amber transition.
• I think the green → green value of 22.18 is larger than it should be because it's including plain file renames.