Since those numbers differ by an order of magnitude, I'm curious to see a more in-depth approach. What percentage of posts by 1-4 edit editors were reverted as vandalism? And how does that compare against those who edit more frequently?
Possibilities to explore:
- Good faith newcomers are getting driven off by aggressive reversion?
- Breaching experiments are on the decline?
I have a hunch that reversion is somewhat more vigilant toward editors who haven't registered, or who have redlinked userspaces. Also have a hunch that there is a large but limited pool of people who conduct breaching experiments without actually intending to contribute. In the latter scenario, most of the people whose main intention is to test the edit function have already written "hi there", gotten reverted, and left.
It might be possible to measure those behaviors in relative terms. One approach would involve tracking how many edits the average new account makes before the user talk and userpage get created, and by comparing the reversion rates of edits from accounts that are fully bluelinked, partially bluelinked (talk page but no user page), and fully redlinked. Another approach would be to parse the rate of short-history editors whose posts include the words "hi", "hello", or "test".