Passionately undeveloped opinions on the state of baseball, the shifting landscape of stats and analysis, and the opiate power of El Pato tomato sauce
Interleague Update: June 24, 2013
We are officially past the halfway point of interleague games in 2013 (2 games past technically) so I’m back with an update on how the scoring has broken down. First and foremost, the AL leads the NL on record, 80-72. Based on pythagorean expectation, the AL should’ve won 80.82 games, the NL 71.18, so we are actually very close to what our run differential suggests. Check out how win expectancy has tracked with actual wins here:
Not too much variation off expected, in fact never more than about 3.5 games.
Run differential itself is a bit more interesting. The AL regained the advantage around game #30 and has never looked back, pushing it as high as 60 in their favor.
Who wants to see stabilized data? Everyone! Runs scored per game has tracked nicely since about game #40, as can be seen below. There’s currently a 0.29 runs/game advantage for the AL (AL: 4.32, NL: 4.03), though both are ever so slightly below their intraleague averages (AL: 4.39, NL: 4.06). I’m going to step out on a limb and assume those aren’t significant differences.
Lastly, I’ve added a histogram of win margin to see if one league or another is posting a lot more 8-run victories than normal. Nearly 75% of both teams wins are of the 1 to 3 run variety, though the AL has more of the 2- and 3-run variety, the NL has more 1-run. Beyond that each league is posting about the same number of blowouts, with the AL having two 9-run victories to the NL’s zero, and two 10-run victories to the NL’s one being the biggest contributors to run differential.
As a whole, the leagues are very well matched up through a 152 games, which should be expected. The AL seems to be making slow but steady progress towards a better record, but the small win margins would seem to indicate it’s fairly luck driven and not necessarily an indicator of a real quality difference between the leagues. I guess the All-Star Game will sort that one out for us! /sarcasm/