At the start of the 2012 Olympics, four women's badminton doubles teams were disqualified for attempting to lose a round-robin game in order to play an easier opponent in the tournament. As the Winter Olympics start tomorrow, I thought it would be a good time to think about how one would determine if Olympians are shirking or tanking, such as to gain an advantage in later Olympic play. I naturally thought about using data to make this determination (please note I do not have this data, so I am unable to do this type of analysis). So I am going to make some assumptions to walk through this type of analysis.
The first area to look at would be serves. This is an area that should give a clean test of shirking/tanking. If the player has a history of international play, then they would have a series of data on their serves, especially in games that are important (winning a tournament, escaping elimination, winning a game, etc.) where they have an incentive to perform at their best, and then look at how the variation in their performance under instances where they have an incentive to perform their best and compare that to their serves if there is speculation of shirking/tanking. Thus as the article mentions, serving into the net (so that their opponent cannot try to unsuccessfully return the shot) would be a very clean test of tanking.
Second would be in service returns, whether they are able to return the serve and the ability to return the serve in play. Again, one could compare the data series (especially if they have played each other before) and see if there is a statistically significant difference between the two.
Third, one could look at joint tests (given the example above is doubles) and test to see how statistically likely it would be for both players to serve poorly.
Finally (OK, maybe not finally - but finally for this blog), one could look at volleys during the match between the player(s) involved to determine if there is some statistically significant differences in performance during questionable play.
More importantly, designing a tournament such that these types of incentives do not exist is also important; and penalizing players - such as international bans by sport federations might also reduce the need for this type of analysis.