In 1973, the American League instituted the DH in order to increase scoring and attendance. It’s now 2016, and there is a call for the National League to adopt the DH for various reasons, including increasing offense. While we can admit a DH is a better hitter than a pitcher, what impact does a DH have upon offense. 

To look at offenses, let’s look at baserunners. The best gauge for baserunners is OBP. Here’s the OBP average per team in the AL and NL the past 10 years:

• 2015: AL .318/NL .316
• 2014: AL .316/NL .312
• 2013: AL .320/NL .315
• 2012: AL .320/NL .318
• 2011: AL .322/NL .319
• 2010: AL .327/NL .324
• 2009: AL .335/NL .330
• 2008: AL .335/NL .331
• 2007: AL .338/NL .334
• 2006: AL .339/NL .334

Even with the automatic pitcher outs, there isn’t a great disparity in the OBP between the league’s. However, there are more baserunners in the AL. As a result, it is reasonable to expect that there will be the average AL team will score more runs over the same timeframe:

• 2015: AL 710/NL 666
• 2014: AL 677/NL 640
• 2013: AL 702/NL 649
• 2012: AL 721/NL 683
• 2011: AL 723/NL 668
• 2010: AL 721/NL 701
• 2009: AL 781/NL 718
• 2008: AL 775/NL 734
• 2007: AL 794/NL 763
• 2006: AL 804/NL 771

Again, it is undoubtedly true the average AL team scores more runs over the course of a season, especially in 2009. However, to determine what impact these additional runs have on a game, we need to look at what the average runs an average team scores per game

• 2015: AL 4.38/NL 4.11 Difference 0.27
• 2014: AL 4.18/NL 3.95 Difference 0.21
• 2013: AL 4.33/NL 4.01 Difference 0.32
• 2012: AL 4.45/NL 4.22 Difference 0.23
• 2011: AL 4.46/NL 4.12 Difference 0.34
• 2010: AL 4.45/NL 4.33 Difference 0.12
• 2009: AL 4.83/NL 4.43 Difference 0.40
• 2008: AL 4.78/NL 4.53 Difference 0.25
• 2007: AL 4.90/NL 4.71 Difference 0.19
• 2006: AL 4.96/NL 4.76 Difference 0.20

So overall, even with the DH, the average AL team does not even score a run more per game than the average NL team. the highest differential over the last ten years was in 2009 when it was 0.40 runs per game. There may be different reasons to explain why these numbers are so close. However, these are numbers are close each and every year over the course of a decade. 

So while many will say the DH increase offense, they would be right. However, they are wrong on the extent of the impact. The impact is essentially negligible.