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):

                                RS^2
    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.
