The Major League Baseball All-Star break is this week, so it’s a good time to step back and review the key statistics to identify the most productive players and teams over the first half of the season.
Following on my latest periodic post on the Stros, regular readers of this blog know that RCAA ("runs created against average") and RSAA ("runs saved against average") statistics, developed by Lee Sinins for his Sabermetric Baseball Encyclopedia, provide a simple but revealing benchmark of how an MLB player or MLB team is performing during the long MLB season.
RCAA reflects how many more (or fewer) runs that player generate relative to a league-average player (an exactly league-average player’s RCAA is zero).
Similarly, RSAA measures how many more (or fewer) runs that a pitcher saves relative to a league-average pitcher (an exactly league-average pitcher RSAA is zero).
Thus, a club’s positive RCAA number reflects how many more runs a club’s hitters are generating relative to what a league-average club would generate using the same number of outs. Likewise, a club’s positive RSAA number reflects how many more runs the club’s pitching staff is saving relative to what a league-average pitching staff would prevent in the same number of innings. Negative RCAA and RSAA numbers are just the opposite. A negative RCAA reflects how many fewer runs a club’s hitters are generating relative to a league-average club and a negative RSAA indicates how many more runs a pitching staff is giving up in comparison to a league-average staff.
Accordingly, focusing on those two basic statistics, let’s review the top players and the top teams from the first half of the 2009 season: