Many times on a TV baseball broadcast (and probably in news articles), I've heard/seen statements like:
- (Player X) is the key to (Team A) because when he hits (much better than normal) when they win, but (much lower than normal) when they lose; and
- (Pitcher Y) needs to be more consistent because he has (great pitching stats) in his wins and (terrible pitching stats) when he loses.
In games they won in 2007, MLB batters as a group:
- hit
- .304/.375/.494 (.869 OPS) w/ .335 BABIP,
- compared to .231/.294 /.349 (.643 OPS) w/ .269 BABIP when they lost
- while ML overall was .268/.336/.423 (.758 OPS) w/ .303 BABIP
- hit 47% more doubles, 74% more triples, 77% more home runs
- scored 219% more runs
- struck out 15% less
- stole 49% more bases at a slightly higher rate (3%)
- grounded into 11% fewer double plays
- reach base on error 41% more
- had nearly double the number of SH and SF
- were three times more likely to be intentionally walked
For example, Jimmy Rollins
- in Wins, .346/.388/.610 (.998 OPS) .348 BABIP
- in Losses, .232/.288/.428 (.715 OPS) .234 BABIP
- overall, .296/.344/.531 (.875 OPS) .300 BABIP
and Shane Victorino
- in Wins, .318/.373/.487 (.859 OPS) .332 BABIP
- in Losses, .231/.312/.338 (.650 OPS) .261 BABIP
- overall, .281/.347/.423 (.770 OPS) .302 BABIP
"(Player X) is the key to (Team A) because when he hits (much better than normal) when they win, but (much lower than normal) when they lose" could be said of either player. (Rollins is more extreme, but it still holds true)
Reverse the wins with losses above and you will see how the pitchers did. Pitchers who got the Win had a 2.27 ERA and pitchers who got the Loss had a 8.38 ERA, and those that did not get a decision had a 4.18 ERA (ML ERA last year was 4.47).
So when they give splits and analysis like that, it is probably true, and probably not that useful.