As the Stros play out the string of the 2006 season amidst the beginning of the football season, the Stros’ lone slugger — Lance Berkman — quietly reached another milestone in his quest to become the best hitter in Stros history.
Over the weekend against the Brewers, Berkman overtook future Hall of Famer Craig Biggio for second place in career runs scored against average (“RCAA”) among Stros players. As regular readers of this blog know, RCAA is a Lee Sinins-developed statistic that is among the best in reflecting the effectiveness of a hitter. The reason for this is that it focuses on the most important statistic in baseball for a hitter — creating runs. Whereas more commonly cited statistics such as batting average can be very misleading (for example, some local media commentators misconstrue Willy Taveras‘ .284 batting average as meaning that he is having a good hitting season), RCAA is particularly valuable in evaluating hitters because it focuses on the two most important things in winning baseball games — that is, creating runs and avoiding making outs.

RCAA computes the number of runs that a particular player creates for his team relative to the number of outs that he makes while creating those runs, and then compares that number of runs to the number that a hypothetical average player in the league would create while using an equivalent number of outs. Inasmuch as the hypothetical average player’s RCAA is always zero, a player can have either an RCAA that is a positive number — which indicates he is an above average hitter — or an RCAA that is a negative number, which means that he is below-average hitter.
Moreover, RCAA is also a valuable tool to evaluate hitting ability because it provides a good measure for comparing hitters who played during different eras. Inasmuch as RCAA measures a player’s hitting ability against that of an average player in the player’s league for each particular season, a player’s career RCAA measures how a hitter compared to an average hitter during that hitter’s career. Thus, comparing RCAA of hitters from two different eras allows us to compare how those hitters produced relative to an average hitter in their particular era, whereas comparisons of other hitting statistics — such as on-base average, slugging percentage, and batting average — are often skewed between players of hitter-friendly eras (such as the past 15 year or so) versus players of pitcher-friendly eras, such as the late 1960’s and early 70’s.
With Berkman passing Bidg in career RCAA over the weekend, the following is the revised Stros top-10 career RCAA list:

In fact, Berkman’s current season is now among the top 10 hitting seasons in Stros history, a category that Berkman and Jeff Bagwell dominate:

Berkman is also 4th in the National League in RCAA since 2000, the year in which he became a regular MLB player:

And he is 8th among all Major League Baseball players in RCAA since 2000:

By the way, on the other side of the RCAA ledger, Stros catcher Brad Ausmus is very quietly putting together one of the worst hitting seasons in Stros history, and is closing in on Roger Metzger’s record worst -37 RCAA for one season. Here are the top 10 worst seasons for a Stros hitter, a category that Ausmus dominates:

Moreover, Ausmus is easily the worst hitter in Stros history:

And Ausmus is the 4th worst hitter in Major League Baseball since 1994, the year in which he became a regular MLB player:

Thus, in Berkman and Ausmus, the Stros have among the best and the worst of hitters. Whether the club during this off-season attracts a couple of hitters with positive RCAA — while foregoing hitters such as Preston Wilson who have negative RCAA — will largely determine whether the Stros will compete for a playoff spot in the 2007 season and beyond.