http://en.wikipedia.org/wiki/Simpson's_paradox http://en.wikipedia.org/wiki/Simpson's_paradox is quite likely ;) There's many other variables apart from the pro

http://en.wikipedia.org/wiki/Simpson's_paradox http://en.wikipedia.org/wiki/Simpson's_paradox is quite likely ;) There's many other variables apart from the programming language itself that affect the salary. They can be only indirectly correlated with the language.