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 ambergreen 447
4.65 amberred 379
4.67 amberamber 1462
5.39 redgreen 607
6.01 redred 604
7.52 greenred 420
13.65 greenamber 436
17.67 redamber 432
22.18 greengreen 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 amberamber transitions (1462). I speculate that long sequences of these transitions are occuring after a large 13.65 greenamber or 17.67 redamber transition.
  • I think the greengreen value of 22.18 is larger than it should be because it's including plain file renames.