Sorry to revive an old topic, but as a fan of clutch hitting, I want to point out that SOM themselves have realized the statistical insignificance of 1 seasons worth of clutch hitting. I don't understand how, but they supposedly compensate for that with each individual player to make it as realistic as possible.
This is taken directly out of the help file from the CDROM version of the game:
"Clutch hitting measures each player's ability to deliver the clutch hit. Strat-O-Matic's exclusive clutch hitting formula accurately measures every player's ability in these key situations. Traditional clutch hitting stats do not comprise enough situations to make them statistically significant. For instance a batter with 500 at-bats might only hit 110 times with runners in scoring position and perhaps 80 times in "close and late" situations. This total number of at-bats is not enough to truly gauge his clutch hitting ability, because in 190 at-bats a .250 hitter can be expected to swing anywhere between .187 and .313 just as a result of random statistical distribution. Strat-O-Matic's exclusive clutch hitting formula measures the outcome of every baserunner that the batter affected during the year. This detailed approach provides a true measurement of the batter's clutch hitting ability. Our system is implemented with 2 outs and runners in scoring position because in real-life that is traditionally the most difficult time to "come through" with a base hit. If the batter fails, there are no more chances to drive in those runners. Most batters will see their average go down in the clutch -- both in real-life and with our system."
Take it for what it's worth, but it seems they tried to take everything they possibly could into consideration.