In 2008/09, Reid Priedhorsky, who studied Wikipedia and similar social projects at the University of Minnesota, estimated in a paper that the chances of any one visitor seeing a damaged Wikipedia page were about one in 140, as the average time it takes to repair damage is less than three minutes, and even less for heavily tracked pages. However, vandalism appears to be on the increase and it is impossible fully to measure the scale of the problem.[1]
