2007 Team efficiency


Measuring team efficiency

By Charles Wolfson and Tom Tippett
December 10, 2007

In the mid-to-late 1990’s, Tom started writing an annual essay about teams whose win-loss records were out of synch with their underlying stats. In the early years, these essays were largely unknown to the baseball community, because they were available only as part of the annual Diamond Mind Season Disk. That changed in 2002, when he wrote an article on the subject for ESPN.com, and they’ve been published on ESPN.com and/or the Diamond Mind website ever since.

The central idea is simple. Baseball analysts have developed a variety of methods for translating (a) hits and walks and other events into runs, and (b) runs into wins. One can use these methods to identify teams that scored more or fewer runs than they "should have," teams that allowed more or fewer runs than they "should have," and teams that won or lost more games than they "should have," given the runs they actually scored and allowed.

In the years since our Team Efficiency article first appeared on ESPN.com, others have picked up the ball and run with it. The folks at Baseball Prospectus created a team standings page, updated daily during the season, which shows the actual standings and the standings as they would appear if every team had "normal" relationships between events and runs and wins. Bill James is now providing information of this type for the annual Bill James Baseball Handbooks. And The Hardball Times Baseball Annual has included a chapter on this subject.

What do we mean by team efficiency?

In a nutshell, you win games by outscoring your opponents, so the connection between runs and wins is very strong, even though every season produces a few teams that win more or less than you'd expect given their run differential. To explore the relationship between runs and wins, we use the pythagorean method that was developed by Bill James.

You score runs by putting together hits, walks, steals, and other offensive events, and you prevent runs by holding the other team to a minimum of those things. In most cases, there's a direct relationship between runs and the underlying events that produce runs.

We use the term efficiency to represent the ability to turn events into runs and runs into wins. An efficient team is one that produces more wins than expected given its run margin, produces more runs than expected given its offensive events, and/or allows fewer runs than expected given the hits and walks produced by their opponents.

In the 2002 edition of this article, we showed that what goes around, comes around: teams that are unusually efficient (or inefficient) have exhibited a very strong tendency to revert back to the norm the next year. That's good news for some teams and bad news for others. If you'd like to find out who falls into which category, read on.

Converting runs into wins

The Bill James pythagorean method is a well-established formula based on the idea that a team's winning percentage is tightly coupled with runs scored and runs allowed. Bill's formula is quite simple ... take the square of runs scored and divide it by the sum of the squares of runs scored and runs allowed (RS = runs scored, RA = runs allowed):


  Projected winning pct =  ------------

                           RF^2 + RA^2

The 2007 season was unusual in that just 15 of 30 teams finished with win-loss records within three games, and just 23 of 30 within five games, of their projected record, compared to 18 of 30 and 25 of 30, respectively, in 2006. From 2003 to 2005, 75 of 90 teams finished within five games of their pythagorean projection.

The great outlier in 2006 was the Indians, who won 12 less games than normal for a team with their +88 run differential. No team approached that level of frustration in 2007, but the Diamondbacks overachieved by nearly as big a margin, winning 11 more games than normal for a team outscored by 20 runs, a margin topped by just four teams since 1974. The Mariners were nearly as fortunate, winning 9 more games than their -19 run deficit warranted.

The Red Sox registered an unusual reversal of fortunes. In 2007 they won a major league best 96 games, despite underperforming their projecting win total by seven games, compared to the disappointing 2006 season in which they managed only 86 wins, but exceeded their projected win total by six.

Baseball history tells us that large deviations are unusual and tend not to be repeated the following year. In our 2006 article, we suggested that the Indians could well see a big improvement in their win-loss record in 2007, even without major roster changes; for the same reason, fans of the Diamondbacks and Mariners may have reason to view the upcoming 2008 season with some trepidation.

Converting offensive events into runs

Just as there is a strong relationship between runs and wins, it's almost always true that the more hits and walks you produce, the more runs you'll score. Sometimes, of course, a productive team comes up short on the scoreboard because they didn't hit in the clutch, didn't run the bases well, or hit line drives right at people in key situations. But this relationship holds up most of the time.

To shed some light on this relationship, we need a way to take batting stats and turn them into a measure of overall offensive production. There are several good options here, including Runs Created (Bill James), Batting Runs (Pete Palmer), Equivalent Average (Clay Davenport), OPS (on-base average plus slugging average), and Base Runs (David Smyth).

For this exercise, we'll use the sum of total bases and walks, or TBW for short. TBW is not a perfect measure, but it does have a few things going for it. It captures the most important things a team does to produce runs -- singles, extra-base hits, and walks -- and it's easy to figure without a computer.

As with other statistics, a team's TBW total can be significantly influenced by its home park. For that reason, we focus on the difference between the TBW produced by a team's hitters and the TBW allowed by its pitchers. This effectively removes the park from the equation and helps us identify teams that outproduced their opponents.

The following table shows the offensive and defensive TBW figures for the 2007 American League, along with the difference between these two figures and each team's league rank based on those differences. It also shows runs for and against, the run differential, and the rankings based on run differential. Finally, because we're trying to trace a path from TBW to runs to wins, it lists the team's win total and league rank for the year.

      ---------- TBW ----------   ------- Runs --------   - Wins -

AL     Off    Def   Diff   Rank   Off   Def  Diff  Rank   Num Rank 

BOS   3170   2620    550     1    867   657   210    1     96   1t
NYA 3286 2907 379 2 968 777 191 2 94 3t TOR 2854 2633 221 4 753 699 54 6 83 7
BAL 2821 2987 -166 11 756 868 -112 12 69 12t
TBA 2969 3224 -255 13 782 944 -162 14 66 14
CLE 2987 2717 270 3 811 704 107 3 96 1t
DET 3109 2966 143 6 887 797 90 5 88 5t
MIN 2671 2831 -160 10 718 725 -7 7 79 8
CHA 2732 2946 -214 12 693 839 -146 13 72 11
KCA 2573 3011 -438 14 706 778 -72 11 69 12t
LAA 2824 2767 57 7 822 731 91 4 94 3t
SEA 2805 2964 -159 9 794 813 -19 9 88 5t
OAK 2934 2784 150 5 741 758 -17 8 76 9
TEX 2870 3022 -152 8 816 844 -28 10 75 10

In 2007 just seven of 14 AL teams had positive TBW differentials and just six outscored their opponents, compared to ten and nine, respectively, in 2006. The AL did not get quite as big a boost from interleague play in 2007, slipping from 154-98 overall vs. the NL in 2006 to 137-115 last season.

Boston dominated the rankings, leading the league in TBW differential, run margin, and wins. Indeed, their +550 TBW was the ninth best out of 928 team seasons since 1974. The Yankees were a solid second in both categories, and were slightly more efficient than the Red Sox in converting their +379 TBW into +191 runs.

As bad as things were for the bottom-ranked teams, for some they could have been even worse. Kansas City managed to better three other AL teams in run differential, despite a major league worst -438 TBW. The White Sox were a comparatively modest -214 TBW, but their -146 run differential was more than double that of the Royals. Nevertheless, Chicago won three more games than the Royals and six more than their second-worst-in-the-majors run differential predicted.

As already noted, Seattle turned in a remarkable performance in 2007, winning 88 games despite ranking ninth in the league in both TBW and run differential. Since 1974, no other team has managed at least 88 wins with a worse TBW than Seattle’s -159. In fact, only eight teams have managed the feat with a TBW in the red at all.

Minnesota and Los Angeles were notable overachievers, each ranking three spots higher in run differential than TBW. The Angels actually had a higher run differential (+91) than TBW (+57), the only team in 2007 to achieve that feat. Whether this run efficiency is a tribute to their “small ball” proficiency, or further obscures the true urgency of their need to boost their offenses, the 2008 season may reveal.

Oakland’s decline in the standings in 2007 was reflected in their inefficiency. The A’s ranked fifth in the league with a +150 TBW, but just eighth with their -17 run differential. Should the Angels do no more than add Torii Hunter, the Mariners come back down to earth, and the A’s keep their pitching corps intact, they may not be as far from contending in the AL West as the 2007 standings might otherwise suggest.

Moving on to the National League:

      ---------- TBW ----------   ------- Runs --------   - Wins -

NL     Off    Def   Diff   Rank   Off   Def  Diff  Rank   Num Rank 

PHI   3246   3104    142     5    892   821    71    4     89   3t
NYN 2971 2842 129 7 804 750 54 6 88 5
ATL 3006 2845 161 3 810 733 77 2 84 7
WAS 2679 2997 -318 16 673 783 -110 15 73 11t
FLO 3044 3170 -126 11 790 891 -101 13 71 14t
CHN 2879 2746 133 6 752 690 62 5 85 6
MIL 3033 2876 157 4 801 776 25 7 83 8
SLN 2747 2922 -175 13 725 829 -104 14 78 10
HOU 2858 3113 -255 14 723 813 -90 12 73 11t
CIN 2983 3078 -95 9 783 853 -70 11 72 13
PIT 2754 3046 -292 15 724 846 -122 16 68 16
ARI 2761 2860 -99 10 712 732 -20 9 90 1t
COL 3111 2881 230 2 860 758 102 1 90 1t
SDN 2862 2583 279 1 741 666 75 3 89 3t
LAN 2788 2722 66 8 735 727 8 8 82 9
SFN 2673 2836 -163 12 683 720 -37 10 71 14t

The NL champion Rockies ranked second in TBW and first in run differential. The team they defeated in the one-game playoff for the wild card, the Padres, did almost as well, ranking first in TBW and third in run differential.

The Diamondbacks, however, were the biggest story, winning 90 games despite a -99 TBW and a -20 run differential. Since 1974, the only other teams to manage 90 wins with a negative TBW were the 1984 Mets (-24) and the 1997 Giants (-9).

In 2006, the Cardinals eked out a division title and a World Series championship, despite a -23 TBW and +19 run differential. We gave them something of a “pass” that year on the basis of lengthy injuries to numerous key players. In 2007, however, the team slipped precipitously to -175 TBW and -104 runs. The fact that they managed to win eight more games than that performance warranted should not mislead anyone into thinking that this is not a team in need of a significant overhaul.

Atlanta was reasonably efficient in converting a +161 TBW (ranked third) into +77 runs (ranked second), but not in turning that positive run differential into wins (ranked seventh). Milwaukee was the league’s most inefficient team, ranking fourth with a +157 TBW but just seventh with +25 runs, a testament, perhaps, to their particularly inept defense.

Looking ahead

As we've pointed out, it's unusual for teams that are especially efficient or inefficient to sustain those levels the next year. Instead, they tend to revert to the normal relationships between TBW and runs and between runs and wins. That means we can identify teams that are likely to improve or fall back even if they don't make moves that change their talent level significantly.

For that reason, the A’s could be a sleeper team in the comparatively weak AL West, with underlying numbers in 2007 comparable to the Angels and overachieving Mariners. And based on their 2007 figures, Red Sox Nation can expect their team to be at least as tough again in 2008.

In the NL, 2008 could be the year the Braves return to the top of the East Division. It’s improbable for any team to put together a run like Colorado did last fall, but there is nothing in the numbers to suggest that the Rockies cannot carry last season’s improvement into 2008. The Diamondbacks, on the other hand, could be making a mistake if they choose to stand pat this winter. And a rebound by the Cardinals, even in the mediocre NL Central, appears unlikely without significant reinforcements.

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