The Wall Street Journal reports that the scientific journal PLoS One published a research study ranking tennis players on a measure different than the usual "most weeks at No.1" or "most Grand Slam championships" - a measure called "prestige scoring."
By 'Prestige Score,' Connors is Tops, Wall Street Journal, February 28, 2011
Based on this study's "prestige scoring" ranking, Northwestern University statistical researcher Filippo Radicchi argued that Jimmy Connors might be considered the "greatest tennis player of all time".
What is "prestige scoring"?
It refers to victories by a player over "quality opponents", as opposed to any win against any opponent. "What's really important is not to win many matches, but to win matches against other good players," explained Radicchi.
Radicchi reviewed and evaluated all matches in the Open Era from 1968 to 2010. He developed an algorithm and applied it to his tennis database. He ranked players based on "quality wins".
And he concluded that Connors enjoyed 178 quality match victories over his career - more than anyone else, and thus achieved 95.4 on his "prestige score". Ivan Lendl came in second with 134 quality wins, and John McEnroe was third with 129 quality wins.
For more reading, see:
Who Is the Best Player Ever? A Complex Network Analysis of the History of Professional Tennis (February 09, 2011)