February 24, 2013

MLB runs allowed by team

Or, How good were the Maddux/Glavine-era Braves?

In this on-going series of posts about run scoring in Major League Baseball, for this installment I'll turn the equation around and look at runs allowed.  In order to account for the changing run scoring environments, the runs allowed by individual teams is compared to the league average for that season, creating an index where 100 is the league average. In this formulation, a score below 100 is a good thing; a team with an index score of 95 allowed runs at a rate 5 percentage points below the league average.

Having written the original code in R, it's now a very simple process to change a few variable names and create the equivalent of the earlier runs scored analysis, but looking at runs allowed. This is one of the most important benefits of a code/syntax environment, an option that doesn't exist if  you are using a point-and-click GUI interface.


In the original data set (the "Teams" table from the Lahman database), the variable "R" is for runs scored and "RA" is runs allowed.  So throughout the code simply changing R to RA will do the trick. For example, the variable "Teams.merge$R_index_rank" is changed to "Teams.merge$RA_index_rank".

Similarly, when it comes time to write the summary tables a simple change within the file name is sufficient. (I chose to change the bit with "off" (for offense) to "def" (for defense), so "Teams.hi_off" becomes "Teams.hi_def".)

NOTE: The R code for this analysis is posted at at Github.  The original code, necessary to process the file and create a data table "Teams. merge" is here, and the supplementary code to incorporate individual team runs allowed is here.

So what are the results?

First, the success stories -- teams that allowed runs at a rate of 80% of the league average.  (For those of you new to the story, I used the period 1947-2012.)  There's only 23 of the 1,580 clubs that played during this period ... and seven of them are the Braves franchise.  They make the list in their first two seasons in Milwaukee (1953 and 1954), and then again in 1958. This was the period when the rotation was anchored by the great Warren Spahn, who was 37 in 1958. The Braves reappear in 1993, when Greg Maddux joined the already-strong rotation that featured Tom Glavine and John Smoltz. That trio was still part of the Braves' staff in both 1997 and 1998.  In 2002 the Braves reappear on the list.  By this time Smoltz was gone, but Glavine and Maddux -- both aged 36 -- turned in ERAs below 3. And this in the midst of the run-scoring bonanza of what is now dubbed "the steroid era".

The only other team with more than three appearances on the list are the Los Angeles Dodgers, who appear twice when Sandy Koufax was on the team (1965 and his final season, 1966).  The 1975 Dodgers pitching staff featured the 2.29 ERA of Andy Messersmith, while in 2003 Hideo Nomo and Kevin Brown were the stars of the rotation.

One other thing that I can't help but note is that the New York Yankees only show up on the list once, in the strike-shortened 1981 season.  Below, we'll take a closer look at the team history.


ROWyearIDlgIDfranchIDRA_indexRA_index_rank
3371966NLLAD73.881
13022003NLLAD74.592
2851964ALCHW76.203
10051993NLATL76.874
6961981NLHOU76.985
191948ALCLE77.056
1161954ALCLE77.127
11461998NLATL77.968
11171997NLATL78.019
3831969ALBAL78.0210
1251954NLSFG78.2411
6271979ALBAL78.4412
15452011NLPHI78.5113
12662002NLATL78.6614
6881981ALNYY78.6715
1081953NLATL78.9116
1241954NLATL79.0917
12312001ALSEA79.6418
2251961ALBAL79.6919
3161965NLLAD79.7420
351949ALCLE79.7621
1881958NLATL79.8722
5431975NLLAD79.8823


Now we'll move to the teams that allowed runs at a rate greater than 20 percentage points above the league average.  There are more than twice as many clubs on this list -- 54 in total.

One of the factors that appears to play a role is expansion.  Some of the clubs on the list were in their first or second years as a new franchise, and the poor quality pitching shows. (While this makes intuitive sense, a closer look at this phenomenon is warranted, along with a comparison of their hitting performances.)

One such team are the Colorado Rockies, whose inaugural season of 1993 makes the list.  What sets the Rockies apart is that they also have six other seasons of allowing runs at a rate more than 20 percentage points higher than the league average.  This in spite of only played in 20 of the 66 seasons in the analysis.  At least to some degree, the well-established phenomenon of a high run-producing environment at Coors Field can explain this.



ROWyearIDlgIDfranchIDRA_indexRA_index_rank
1191954ALOAK133.891580
10081993NLCOL132.971579
1341955ALOAK132.301578
2581962NLNYM131.391577
1001953ALDET130.991576
15692012NLCOL129.021575
11791999NLCOL128.071574
1521956ALMIN128.011573
14432008ALTEX127.611572
10921996NLCOL127.051571
10801996ALDET126.381570
2881964ALOAK126.381569
391949ALBAL126.051568
5891977NLATL125.531567
2781963NLNYM125.381566
12692002NLCOL124.251565
1681957ALMIN124.071564
6121978ALSEA123.991563
11501998NLFLA123.841562
3041965ALBOS123.831561
5401975NLCHC123.711560
711951ALBAL123.641559
13522005ALTBD123.441558
5241974NLSDP123.421557
13462005ALKCR123.301556
13762006ALKCR123.121555
12332001ALTEX122.951554
15162010NLPIT122.831553
5161974NLCHC122.831552
12932003ALTEX122.761551
2721963ALTEX122.751550
951952NLPIT122.601549
7811984NLSFG122.551548
13292004NLCOL122.361547
791951NLPIT122.151546
3341966NLCHC121.981545
10541995ALMIN121.961544
11201997NLCOL121.911543
4901973ALTEX121.821542
4101970ALCHW121.771541
3721968ALTEX121.251540
1111953NLPIT121.161539
14122007ALTBD120.871538
13582005NLCIN120.831537
2841964ALBOS120.621536
401949ALMIN120.611535
4671972NLATL120.581534
8391987ALCLE120.571533
9271990NLATL120.541532
4001969NLWSN120.431531
3751968NLCIN120.381530
13282004NLCIN120.241529
1271954NLPIT120.201528
14902009NLWSN120.191527


And similarly, we can look at a single team's performance over time with a few adjustments to the R code.

When looking at run production, the Seattle Mariners were one object of attention. So let's even things up by looking at their pitching since 1977.  They started out, like all expansion teams, with poorer than average performance ... their worst ever year was 1978, nearly 24 percentage points above the league average rate of runs allowed. In recent years, the Mariners have had four seasons of better than average performance. Having Felix Hernandez doesn't hurt, and neither does that fact that Safeco Field tends to play as a pitcher's park.

(click to enlarge)
The Yankees are another story.  Above, I noted that the Yankees only make the list of teams with seasons allowing runs at a rate lower than 80% of the league average only once since 1947. What isn't obvious from that truncated list is how infrequently the Yankees have allowed runs at a rate higher than the league average -- only eight of the 66 seasons from 1947-2012.  Of those, five were consecutive, 1988-1992. The others were 1967, 1975, and 2005.

The inverse of that are the many seasons that the Yankees have had allowed far fewer runs than the league average. Coupled with the similarly dominant offensive performance identified in the earlier post, there is no wonder that the Yankees are (arguably) the most successful professional sports franchise in the world.

(click to enlarge)

And finally, the Braves, who we saw earlier had an unusually large number of appearances on the low number of runs allowed side of the ledger. As noted earlier, the franchise's first few years in Milwaukee (starting in 1953 and ending in 1965) were marked by strong pitching.  But nothing in the team's history can match the Maddux-Glavine era -- the ten seasons from 1993 through 2002 -- where the run suppression was consistently outstanding.

(click to enlarge)


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