Science, Innovation, Politics
I think this is essentially a risk management problem a la climate change.While human evolution is a chaotic process, it exhibits remarkable stability over extended periods (i.e. months, years), which can be analyzed statistically. Along with characterizing external factors, this may be sufficient to describe a bounding envelope. Perhaps instead of detecting performance enhancing drugs, it would be sufficient to trace individual performance over variable periods. It seems that the goal is not to detect chemical stimulants per se, but effects that produce observable outcomes which merit external scrutiny.
Football does have a slight luck of the draw factor built into the game rules, which make scoring so difficult, and this means missing by one cm in a single tenth of a second can make the difference. The injury factor is also important, consider the way Brazil fell apart when they lost Neymar. Many of you may not be familiar with Di Maria, who missed the final for Argentina. I tend to believe his injury made the difference in that championship game. As for using the transfer market values, they may be too naive, because they underprice older players who may be able to contribute to a winning run but aren't going to fetch the same price as a greener less tested player felt to have a great potential. A good example could be the transfer market value for Radamel Falcao, who may be the best striker in the world, versus the younger James Rodriguez, who just transferred to Real Madrid for 63 million £.