IN 1996, Rakesh Vohra, a professor at Northwestern University, and his colleague Dean Foster published "A Randomized Rule for Selecting Forecasts," a paper in the journal Operations Research. It illustrated how a random investor could outperform a group of professional stock pickers simply by following a "buy and hold" investment strategy.
It was important research, the authors believed, until they learned that the same discovery had been made at least 16 times since the 1950's.
I would guess this doesn't happen in archaeology that often, at least I've never heard of it before. One would think it would be rare because we're generally a site-specific bunch and it's pretty obvious when the site you're working on has been dug before. Since, you know, ancient peoples probably didn't dig square holes and put all the dirt from them into a few piles close by that often. Even lit reviews that cover the same topic can generally be said to bring a different perspective on things.