Roger Federer's loss in the just concluded French Open finals will naturally ignite the ususal round of questions about his competence on clay. Critics will argue that this is further proof of the fact that he does not belong to the top rank of clay court players of all time.
Now let us examine this claim against the weight of facts. Since 2004, Federer has lost at Paris before the finals to just three players, all of whom were exceptional clay-court specialists. In 2004, he lost to three-time champion and arguably the best clay court player of his time, Gustavo Kuerten, in 2005 to the great Nadal, and in 2010 to two-time finalist (and at the time, red-hot on clay) Robin Soderling. Underlining his consistency on clay, in the past eight years Federer has entered the finals five times, won once, and lost four times (all to Nadal). His record, atleast in terms of finals and consistency on Parisian clay, is bested only by Borg and Nadal.
None of this would speak of a man whose competence on the red clay is questionable. In fact, his consistency alone should place him alongside all the great clay-courters of the open-era, like Guillermo Vilas, Borg, Wilander, Lendl, Courier, Kuerten, and Nadal. Further, his performance on his less favored surface should also be seen against the relatively poor performance of the other great non-clay champions like McEnroe, Becker, Edberg, and Samparas. So why the controversy?
It can be partially explained by a cognitive bias to which human beings are vulnerable - representativeness bias. It refers to the phenomenon where people evaluate a hypothesis (or its probability) by considering how much of it resembles readily available and salient data as opposed to using a Bayesian calculation.
People evaluate great champions by their wins, not their losses. In Federer's case, there are several factors that amplify the bias. Not only has he lost four finals, he lost all of them to his great opponent Nadal, who has won six. Nadal is the unquestioned clay court champion of his time, probably of all time. Federer falls terribly short in comparison to Nadal, atleast on clay. Further, people also compare his performance at French to the other Slams, where he has won 15 times. He has won on grass and hard-courts, despite Nadal. Though it only means that Federer is more comfortable and more competitive on these surfaces, people construe it as proof of his weakness on clay.
In conclusion, Federer may be a lesser player on clay, but less stronger and consistent than only two others!