The study makes a huge swath of unjustified assumptions about Wikipedia vandalism. The biggest one seems to be the assumption that vandalism is randomly distributed amongst articles.
The problem is that our illustrious idiot used an inappropriate methodology to select edits for review. The only statistically meaningful way to do a vandalism study is to select all edits, or a random subsampling of edits, over a particular timeframe, and review each one independently to determine what sort of edit it is. Once you've identified each of the subject edits, then and only then can you step forward in the history of the relevant articles.
Article-based sampling will almost always bias the results to favor apparent stability, because most Wikipedia articles are barely ever edited (and thus barely ever vandalized).
QUOTE(thekohser @ Thu 25th June 2009, 8:25am)
Suppose I entered a nice, juicy, devious vandalized edit on January 1, 2009 on the article about [[Yellowfin tuna]]. Suppose, then, Jon Awbrey comes along on June 24, 2009 and makes a blunt, obvious, profane edit to the article. Jon's edit is discovered by the "Recent Change Patrol", and it is reverted in one minute. However, my edit from January remains safely in place.
The "double whammy" is one of the most common ways that persistent vandalism gets inserted into Wikipedia. I've even seen vandalism patrollers fight IPs to keep double-whammy vandalisms in because they can't be bothered to actually read whatever it is they're reverting. I suspect that some vandals have taken to using multiple accounts (or IPs) just so they can take advantage of this particular foible of the Twinkle-heads.
QUOTE(Peter Damian @ Thu 25th June 2009, 5:43am)
This study is meaningless as statistics without a precise definition of 'vandalism'.
Indeed; the typology of individual edits is more complex than "vandalism" or "not vandalism". I'd probably have categories such as "Garbage edit", "Apparent blanking", "Apparent test edit", "Technical maintenance", "Copyedit", "Minor addition of information", "Substantial addition of information", and "Substantial rewrite", and then additional axes to these valuing the edit as "positive", "negative" or "neutral" to the overall value of the content.