Jay JG wrote I really can't give any credence to the idea that edit wars could pull up the numbers much, averaged over the 400000 pages of the English Wikipedia. Not enough editwarriors to go round. In fact I would argue the diametrically opposite position. The general line of talk that WP is in some way failing/is getting filled with rubbish/is losing credibility/has a serious IP vandal problem/is not applying adequate scholarly standards is based, as far as I can see, on very thin anecdotal evidence. Except for the last of those gripes, it all seems itself to be very much open to a counterattack along the lines that it is only marginally credible, and depends on a highly selective, even panicky, reading of the quantitative facts. Putting it another way, no decent Wikipedia article about WP could contain a sentence like 'in 2004 unregistered vandals were a serious threat to WP'; that would get shouted down as POV, and probably with a hidden agenda. And I think clicking Random Page 100 times supports the impression that things improve. One example is that the category system has come on well, over the past three months. Charles

Jay JG wrote well, Not really. It's a repeatable experiment, and can produce confidence in its results as it is repeated. For example noting the number of uncategorised pages in 100 random ones gives an estimator of the proportion in the whole. Do it a few times, and the estimated proportion should settle down to the real figure. That does assume that Random Page is uniform over all main space pages (which might be wrong). Charles