By The Numbers: The Impact Of Baseball's DH
By Father Gabe Costa
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Our guest blogger, Ted MacDonald, is from the Hub City and was named after Theodore Samuel Williams himself. Like several previous bloggers, he is taking a course on sabermetrics. What follows is an interesting discussion on the designated hitter.
Ted MacDonald: To baseball purists, the designated hitter (DH) is an abomination of the game of baseball. For better or worse though, the DH has allowed sluggers (who may be aging or not-so-good at fielding) to play a pivotal part in the game since 1973. In that time many greats such as Don Baylor ('79 MVP who started nearly half his games as DH), Harold Baines (most career RBI for anyone not in the Hall of Fame), Paul Molitor (3,000 hits and 500 stolen bases), Frank Thomas (The Big Hurt – need I say more?), and Edgar Martinez (perhaps the best DH ever) have excelled in this role. No matter a fan's stance on the DH though, all fans can agree that winning is the bottom line.
Since the inception of the DH, the AL has won the World Series 21 out of 37 times, or 56.8%. Some might say that the AL has a distinct advantage by having a DH and cite this as proof, but compare the fact that since the beginning of the World Series in 1903 (well before the DH), the AL has won the Fall Classic 58.5% of the time. So, in fact, the "DH era" in baseball has actually not lived up to the AL's overall winning percentage. To further pursue the impact of the DH on an American League team, several tests were done to see how much a DH helps his team.
The first analysis was done using what's called Runs Created. This school of thought was originated by Bill James, who revolutionized baseball statistics. In this school, a metric is used to derive how many runs for which a player was "responsible". In this test, the cumulative statistics for the entire NL and AL per year were used instead, to gauge how the leagues compared with each other. Over the last 20 years in which the World Series was played (1990-2010, omitting 1994 due to the strike), the AL had a higher total runs created every single year, and averaged over 40 runs better than the NL. This makes sense since the additional bat in the DH would contribute more runs to the team. However, the AL has only won the World Series 12 of the last 20 times despite the lopsided runs created. With this in mind, the runs created school is lacking in explaining the impact of the DH.
Another major school of thought in baseball stats is called Linear Weights. The linear weights school places increasing values for the "magnitude" of the hit (home runs are worth more than triples, which are worth more than doubles, etc.), adds a factor for walks and hit batsmen, and takes away value the less often a player gets on base. The linear weights instrument, which was developed by gurus John Thorn and Pete Palmer, were then calculated for each team that competed in the World Series over the past ten years (2001-2010). Over this time interval, both leagues have won the World Series five times, and in fact the team from the NL had a higher linear weights value six of ten times, with an average roughly 10% higher than the team from the AL.
What's most intriguing about linear weights is that the team with the higher linear weight won seven of the last ten championships, a pretty good predictor. However, of the last five times the AL team has won, they only had a higher linear weights value three times. This truly does question the value of the DH for the AL team, as they managed to win the World Series almost the same number of times regardless of whether their linear weights was higher than the team from the NL. So, what then, did the DH have to do with that?
The answer to that question came from a useful statistic available at baseball-reference.com. In any given chart for a team over the course of a season, the website ranks players by their "Team Player Value." One of the statistics in this chart is called Rbat, which is defined as "the number of runs better or worse than average the player was as a hitter" and is attributed to Sean Smith of baseballprojection.com. The Rbat statistic was evaluated over the last ten World Series for the DH of the AL team. Of these last ten years, the average Rbat value was 18.4, with five DH's having a higher Rbat and five lower (ranging from Carl Everett's -3, to David Ortiz's +59). What was most telling of this average was that when a team's DH had a Rbat value over the average, their team won the World Series four out of the five times. Conversely, when the team's DH had an Rbat lower than the average, the team only won once of the five times. Although the sample size of ten years is rather small, this suggests that 80% of the time the AL won the World Series (or lost it 20% of the time) depending on the DH's Rbat value in comparison to the average.
This analysis could be improved by increasing the sample size to when the DH came into play. Additionally, the DH is far from the only factor in the strength of a team. This entire analysis has omitted pitching and fielding, and largely disregarded the batting of the other eight players on the field. However, perhaps the value of the DH can now be better understood. Also, the fact that both teams in the World Series either play with or without a DH, depending on the home ballpark, has not been modeled at all. Overall, the "DH era" has not added to the AL's winning percentage in the World Series, it has actually gone down. Designated Hitters do add to a team's offensive output, as evidenced in runs created, but that doesn't equate to a World Series win. The same is true with regard to linear weights, as that statistic lacks solid evidence for AL teams. However, teams may take note that it is not the fact that they have a DH, but rather how productive a hitter truly is when compared to his peers, that may help get a ring.
I close by including several references and an Excel document.
Works Referenced
Abdalla, Pat. "The 10 Best Designated Hitters of All Time." Yorkblog.com, "Southpaw". http://www.yorkblog.com/southpaw/2010/05/post-16.html (Accessed 25 April 2011).
"Baseball-Reference Playoff and World Series Index." Baseball-Reference.com. http://www.baseball-reference.com/postseason/ (Accessed 25 April 2011).
"List of World Series Champions." Wikipedia. http://en.wikipedia.org/wiki/List_of_World_Series_champions (Accessed 25 April 2011).
What's your take on the DH? Be heard in the comments below...
