Tiger Woods or Roger Federer

It is very difficult to compare atheletes which compete in totally different sports. The longevity that a PGA golfer has in his sport compared to that of a tennis professional allows him to persue goals well into his fifties. So in that respect the golfer has an advantage over the tennis player. The tennis player actually competes against other players, in a true head to head volley of the object ball. The golfer, although competing to win a tournament, is trying to defeat the course he is playing. No one golfer has an advantage over another, they all play the same golf course. One golfer cannot affect the flight of another golfers shot into a green or the line of his putt. A tennis player has to play different opponents during the course of his tournament. He is faced with other challenges that can benefit or work against him during the course of his tournament. I would better phrase the question as, "Who has accomplished more in his sport?" That answer will not be heard until after they retire. Another benchmark of great players in their respective genres is, "Have they changed how the game is played?"That my friend is the true mark of a great athelete.