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Scoring by inning: AL vs NL (PART 2)

Posted by Andy on November 5, 2007

OK, here is part two of yesterday's post.

Yesterday, we saw that representing runs scored by inning using percentages was a bit misleading. Here, instead, is average run scoring by inning, AL vs NL. The results are averaged by team, and also averaged over the period 2003-2007:

So what this tells you is that an average team scored about 96 runs in the first inning (totaled over the course of the season.)

As you can see, the AL and NL averaged virtually identical numbers in the first inning (so that paragraph I wrote yesterday wondering why the NL seemed to score more in the first inning was a waste of everybody's time...sorry 🙂 )

But then the NL scoring drops way off in the 2nd inning and 3rd inning, trailing the AL all the way until about the 7th or 8th inning, when the gap closes.

Let me re-display the above graph in terms of difference seen in the NL, using the AL as the baseline:

So you can see that there's virtually no difference in the 1st inning. The second and third innings are the biggest disparity, in terms of fewer runs scored in the NL vs AL, at about 12% each inning.

I submit to you that essentially the entire difference in run scoring between leagues is due to the pitcher batting in the NL. Looking at the above graph, consider the following:

  • There is no difference in the 1st inning because the pitcher never bats unless the batting team has already scored at least 3 runs.
  • The 2nd and 3rd innings are those where the pitchers bat most often and where the NL falls the shortest of the AL.
  • In these days of very few complete games, pitchers rarely bat in innings 7 through 9 (either pinch-hitters are used, or double switches are made to avoid the pitcher's spot from coming up) and the NL just about catches up with the AL in those innings.

Don't believe me? Here is one more piece of evidence.

Using the PI Team Batting Event Finder, here are all of the plate appearances this season by pitchers, broken down by inning:

Notice anything interesting? This graph almost an exact inverse of the run-scoring deficiency by the NL. To me, it's very clear that the more pitchers bat, the fewer runs get scored in the NL. (By the way, the graph above of pitcher PAs does not exclude AL pitchers batting, but obviously they are a small minority of the total pitcher PAs. Also, the above graph is for 2007 only, but I also graphed it for the average of 2003-2007, and the graph looks virtually identical. If I put both lines above, you'd barely notice any difference.)

Also yesterday I said I'd post something about detailed run-scoring in the 2nd or 3rd inning. I looked at that (specifically number of 1-, 2-, 3-, 4-, or 5+ innings by AL teams vs NL teams) but I didn't find anything worth mentioning.

Regarding the difference of run-scoring between the AL and NL, I say case closed.

What do you say?

7 Responses to “Scoring by inning: AL vs NL (PART 2)”

  1. vonhayes Says:

    Great posts. Your conclusion seems pretty solid.

    I'd be interested to hear counter-arguments. I just don't think that the overall style of play is any different between the two leagues, in this day and age, and would not be a suitable explanation.

  2. Andy Says:

    Oh yeah--I don't think style of play is different either. As I wrote above here, my paragraph about style of play in the previous post is just wrong.

  3. ABL73 Says:

    Andy...two very interesting and solid posts. Actually my first day here after seeing the link on bblog ""

    There is no doubt the pitcher batting in the NL causes runs to go down.

    It was also interesting to see the dominance in closers as the run production drops for both leagues in the 9th inning. Is the drop also from the home team not having to bat when leading?

  4. Andy Says:

    Yes---Part 1 of this post from yesterday explains about the drop in the 9th inning being due to home teams winning and closers.

  5. Johnny Twisto Says:

    That 2nd graph is very interesting. Not surprising at all, but to see it laid out like that is fascinating.

    Some the remaining difference between AL/NL over the last few innings is that PH have an inherent disadvantage. I believe Tango and MGL's _The Book_ touched on this more extensively. Players do not hit as well when acting as PH, on top of PH usually being inferior hitters to begin with (not inferior to those they replace, of course, but compared to regulars).

  6. ABL73 Says:

    Andy...thanks...I went back read the first post.

    Johnny...excellent point about pinch hitters. It makes sense they would not fare as great as a full time DH. Plus most pinch hitter aren't tehbest hitters or they would be already be playing or in the AL.

  7. zeke003 Says:

    Great info! I wonder how much additional support an analysis of "plate appearances by position," leaving pitchers and DH's out of each league would show. I think it would lean toward many more at bats for the AL, thus more run production due to higher team BA in the AL. DH's don't just improve a team's offense by their difference between them and pitchers, they also keep innings alive where pitchers just quietly K and sit down. Its a multiplier.