In examining data since 1996, The Economist found that spending on player pay explains 55 percent of the variation in clubs' performance.

Manchester City won their second title in three seasons on Sunday and are the richest club in the league, spending $550 million last year.

But manager performance can make a great impact as well.

Over 19 seasons, Alex Ferguson gained 15 points more on average than would have been expected given the amount Manchester United spent on wages. If Ferguson had been an average manager, he would have won just one title instead of 11.