Saber Correct Tigers, Efficient Athletics

Many fans complained that the Tigers left too many runners on base and did not get the most out of their offense this year. Some said the same thing about the 20o7 and 2008 teams. In actuality, the Tigers scored almost exactly as many runs as they should have given their totals of hits, walks and various other positive batting events in both 2007 and 2008. Today, we'll take a look at 2009.

The Tigers finished tenth in the league with 743 runs scored in 2009. Should they have gotten more runs from their offensive output? One way to answer this question is to look at weighted runs created (wRC). wRC is calculated from the number of walks, singles, doubles, triples, home runs and other things that a team does to score runs. The formula for wRC is a bit involved but the idea is that different batting events are given different weights according to how much they contribute to runs scored:

BB 0.31

HBP 0.34

1B 0.47

2B 0.77

3B 1.04

HR 1.40

SB 0.20

CS -0.42

From examination of thousands of games, it has been determined that, on average, a single contributes 0.47 runs. That is, if you add one single to a team's hit total in each game for 100 games, you can expect that to add 47 runs to their season total. The values for the other events can be interpreted similarly.

Applying the above weights to a full season of plate appearances yields a team's wRC. Table 1 lists the runs, wRC, difference between runs and wRC and % difference for all American League teams in 2009. Table 2 does the same for National League teams. The first thing you should notice is that all but 3 teams in the majors had wRC estimates within 5% of their actual runs scored. This means that wRC gives a good estimation of runs scored in most cases.

A closer look at table 1 shows that the Tigers had 739 runs created in 2008. So, their 743 runs scored was almost exactly as many runs many runs as would have been expected given their offensive output. That tells us that the Tigers were neither efficient nor inefficient with their offense. They were an average team in terms of making the most of their base runners.

The American League team which got the biggest bang out of their offensive output was the Oakland Athletics. Yes, Billy Beane's collection of softball players who clog the bases and don't play the game the right way had the most efficient offense in the majors. The Athletics scored 50 more runs than their runs created estimate. One reason for this was that they were the best base running team in the Majors according to the Equivalent Base Running (EqBRR) statistic at Baseball Prospectus (Base running skill beyond SB/CS is omitted from wRC). Based on EqBRR, the Athletics created 12.5 more runs with their base running than the average team.

The least efficient AL team might also surprise some people. The New York Yankees led the Majors in runs scored with 915 but should have created 971 according to their wRC. One reason for the discrepancy is that the Yankees did not hit as well with runners in scoring position (.766 OPS) as they did with the bases empty (.854 OPS).

Table 1: Efficiency of American League Offenses in 2009

Team	Runs	Runs Created	difference	% difference
Athletics	759	708	51	7.2
Angels	883	843	40	4.7
Rangers	784	758	26	3.4
Royals	686	677	9	1.3
Twins	817	807	10	1.2
White Sox	724	718	6	0.8
Tigers	743	739	4	0.5
Orioles	741	738	3	0.4
Indians	773	780	-7	-0.9
Blue Jays	798	807	-9	-1.1
Red Sox	872	882	-10	-1.1
Mariners	640	651	-11	-1.7
Rays	803	821	-18	-2.2
Yankees	915	971	-56	-5.8

Table 2: Efficiency of National League Offenses in 2009

Team	Runs	Runs Created	difference	% difference
Giants	657	607	50	8.2
Reds	673	659	14	2.1
Cardinals	730	719	11	1.5
Pirates	636	633	3	0.5
Marlins	772	769	3	0.4
Dodgers	780	779	1	0.1
Phillies	820	821	-1	-0.1
Brewers	785	786	-1	-0.1
Rockies	804	807	-3	-0.4
Diamondbacks	720	724	-4	-0.6
Padres	638	642	-4	-0.6
Braves	735	746	-11	-1.5
Cubs	707	719	-12	-1.7
Astros	643	655	-12	-1.8
Nationals	710	737	-27	-3.7
Mets	671	698	-27	-3.9