So a solo home run is actually worth 12.9 points because a solo home run automatically counts for a hit, a run scored, an RBI, and a home run. Pitchers earn 2.5 points times the difference between their innings pitched and the number of earned runs they allowed. Pitchers also earn 3.65 points times the difference between their strikeouts and walks issued. An interesting side note to a pitcher's performance score is that he can actually earn a negative performance score if he is shelled in the game. If he gives up more than 1 earned run per inning and walks more batters than he strikes out, he will have a negative performance score.
Pitchers are the only athletes who can earn negative performance scores.
All other athletes earn 0 performance points on their worst days. Golfers are rated based on their relative position at the end of each round of a tournament. Then those points are multiplied by a factor determined by the round. After the first round the factor is 0.7. After the second round the factor is 0.9.