MEASURING TEAM EFFICIENCY

December 10, 2008

In the mid-to-late 1990’s, Tom Tippett 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 2008 season reverted back to form with 18 of 30 teams finishing
with won-loss records within three games, and 26 of 30 within five
games, of their projected record, compared to 15 of 30 and 23 of 30,
respectively, in 2007.  From 2003 to 2006, 100 of 90 teams finished
within five games of their pythagorean projection.

The great outlier in 2007 was the Diamondbacks, who won 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
nine more games than their -19 run deficit warranted.  As expected,
both teams came back down to earth with the D'backs one game worse
than expected in 2008 and the M's five.

The Angels were the great overachievers this season by also winning 11
more games than their 68 run difference usually produces.  The Astros
were almost as efficient winning nine more games than expected.  On the
other side of the coin, the Blue Jays squandered eight games

Baseball history tells us that large deviations are unusual and tend not
to be repeated the following year.  There has already been some player
movement this winter and it sounds like there's more big signings and
deals yet to come.  But with that in mind, don't expect the Angels and
Astros to be as lucky and the Jays to be as unlucky as they were in 2008.

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 2008 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

TBA   2967   2726    241     3    774   671   103    3     97    2
BOS   3149   2685    464     1    845   694   151    1     95    3
NYA   2916   2734    182     4    789   727    62    7     89    4
TOR   2719   2542    177     5    714   610   104    2     86    7
BAL   2917   3102   -185    12    782   869   -87   12     68   13

CHA   3025   2775    250     2    811   729    82    5     89    4
MIN   2830   2872    -42    10    829   745    84    4     88    6
CLE   2911   2816     95     6    805   761    44    8     81    8
KCA   2618   2829   -211    13    691   781   -90   13     75   10
DET   3076   3101    -25     9    821   857   -36    9     74   12

LAA   2768   2720     48     7    765   697    68    6    100    1
TEX   3242   3227     15     8    901   967   -66   11     79    9
OAK   2583   2691   -108    11    646   690   -44   10     75   10
SEA   2612   3044   -432    14    671   811  -140   14     61   14

In 2008 eight of 14 AL teams had positive TBW differentials and eight
outscored their opponents, compared to seven and six, respectively,
in 2007.  After a short respite in 2007 when they "only" went 137-115
against the NL, the AL stormed back to a 149-103 record.  That
difference is remarkable until you remember that they went an even
more incredible 154-98 in 2006!

As usual, Boston dominated the rankings, leading the league in TBW
and run differentials by healthy margins but they weren't nearly
as efficient as the Angels and Rays in turning them into wins in
the standings.  The Angels were incredible only netting a plus 48
bases in TBW, turning that into 68 more runs, and grinding them into
38 more victories.  We weren't at all surprised to see them lose to
Boston in the first round of the post season though.

Similar to last season, the Twins, like the Angels, were very efficient
with their runners when it came to turning them into runs.  It's not
often that a team can turn a negative 42 bases into a positive 84 runs
but they managed to do it.

The bottom dwellers generally deserved where they belonged. The Royals
did squeeze out four more wins than their TBW and run differentials suggests
but that's small consolation.  Unlike KC, the Tigers went in the opposite
direction going from bad to worse.

Toronto was an interesting team producing the league's fifth best TBW
margin, efficiently converting them to the second best run differential,
only to squander them back to only the seventh best record.  Basically
they were picking teams' pockets for runs only to have their own picked
for victories.

Moving on to the National League:

      ---------- TBW ----------   ------- Runs --------   - Wins -
NL     Off    Def   Diff   Rank   Off   Def  Diff  Rank   Num Rank

PHI   2998   2813    185     4    799   680   119    2     92   2
NYN   2976   2802    174     5    799   715    84    3     89   4
FLO   2922   2825     97     7t   770   767     3    8     84   7
ATL   2904   2902      2     9    753   778   -25    9     72  12t
WAS   2582   3003   -421    15    641   825  -184   16     59  16

CHN   3111   2718    393     1    855   671   184    1     97   1
MIL   2936   2773    163     6    750   689    61    4     90   3
HOU   2710   2911   -201    12    712   743   -31   10     86   5t
STL   3019   2922     97     7t   779   725    54    5     86   5t
CIN   2789   3082   -293    13    704   800   -96   12     74  10t
PIT   2743   3243   -500    16    735   884  -149   15     67  14

LAN   2738   2545    193     3    700   648    52    6     84   8
ARI   2831   2631    200     2    720   706    14    7     82   9
COL   2878   2980   -102    10    747   822   -75   11     74  10t
SFN   2571   2874   -303    14    640   759  -119   13     72  12t
SDN   2688   2841   -153    11    637   764  -127   14     63  15

The Dodgers and Diamondbacks appear to be joined at the hip.  Both
boast similar TBW margins, both have trouble turning them into runs,
and both continue the same downward trajectory with an inability to
turn all that into wins.  These teams are made for each other.

Unlike last season when the Diamondbacks turned the SABRmetric world
on its head, there's no big story to report in the NL.  Basically the
best teams in the divisions won and the worst teams lost.  The Astros
will likely drop a spot or two and the Braves may move up one
but that's just rearranging deck chairs on the Titanic.  Both teams
have a lot of work to do in the off-season before they're back to
being serious contenders.  And the NL is going to have raid a lot of
talent from the other league before they catch even a whiff of parity
next season.

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.

With that in mind, teams that look poised to return to that normal
relationship appear to be the Angels to slide and the Jays to climb in
the AL and the Braves to improve and the Astros to drop in the NL.
Normally that would be good news for Toronto and bad for Los Angeles
but thanks to geography, that's not the case.  The West is so weak
that the Angels still remain the early favorite whereas the Jays
suffer in the best division in baseball.  Even with a return to
expected wins, we're talking about moving up from 4th to 3rd.  In most
other divisions in both leagues, they'd be contenders unlike the
East where they have to battle with three other strong teams.  As
for the Astros and Braves, we expect to see some movement back to
normal but unfortunately for both of them, they're only fair to middling
teams so neither one, regardless of their direction, figure to be
playing for a post season berth.
