"Inquiring Minds Want to Know" edition of Talking Sabermetrics
It's not alway fun following the Astros' performance this year. Indeed, you have to savor the sporadic wins. So, just for peace of mind, I will step back from the overall sabermetric stats for this Astros team. Instead I'll answer a few random Astros-related questions. The questions aren't necessarily sabermetric subjects, but they are susceptible to being answered with sabermetric data sources.
Question: The Astros' pitching has given up a lot of runs. But is this due to the high powered offenses that they have played so far this year?
Answer: In part, yes. I say, "in part" because I don't want to make excuses for the Astros' pitching. According to Baseball-Reference's pitcher player value statistics, the Astros have faced the second highest level of opponent offensive strength among American League teams. Only the Baltimore Orioles have faced better average offensive opponents this season. (See the "RA9opp" stat here.) On average, the Astros have faced opponent offenses which are 5% better than other AL teams. Unfortunately, this doesn't come close to erasing the 36% differential between the Astros' runs allowed and the AL's average runs allowed. (So much for keeping our peace of mind in these answers.) But if you had the hazy feeling that the Astros seemed to be pitching against a lot of good offensive teams, the stats back you up.
Question: Among starting pitchers in the majors, does Bud Norris have the biggest gap between Home and Road pitching performance?
Answer: Yes. Since the beginning of the 2012 season, Norris has an ERA of 7.07 on the road and 1.89 at home---a gap of 5.18 ERA between home and road. At home, Norris is the third best pitcher in baseball over that period, behind only Justin Verlander and Clayton Kershaw---but he is the worst pitcher in baseball on the road. The Pirates' James McDonald appears to have the second biggest gap between home and road for that period: 6.45 ERA on the road and 2.78 at home. McDonald's 3.67 gap between home and road ERA pales in comparison to Norris' 5.18 gap.
The gap between Norris' home and road FIP for the same period is 2.37, which also appears to be the highest among major league starters. But the fact that Norris over performs his FIP at home (ERA is 1.03 lower) and under performs his FIP on the road (ERA is 1.72 higher) suggests some luck in his H/R performance split.
For whatever reason, Norris has more pitches called balls on the road than at home (38% vs. 34%). Is his control worse on the road, or do umpires favor the home team in balls/strikes calls? I can't resolve that question, but the disparity in Norris' non-strikes thrown at home and on the road contributes to a significant gap in his strike out rate (24% vs. 18%) and walk rate (6.8% vs. 10.8%) at home and on the road.
Norris is also much more effective at controlling lefthanded hitters at home compared to the road. For the same time period, Norris held lefthand batters to a lower BABIP than righthand batters (.266 vs..288) at home. Overall for the period, Norris' home BABIP (.279) is much lower than his road BABIP (.335). But, perhaps more interestingly, Norris has a BABIP against lefthanders (.357) on the road which is almost 44 points higher than the road BABIP for righthand hitters (.313). To some extent, this may reflect Norris' ability to use Minute Maid Park's dimensions to suppress lefthanded batters, who seem to be Norris' nemesis on the road.
Question: Do the Astros' batters strike out so much because they are too passive?
This question, itself, may draw a "What?" exclamation. Normally we don't associate strike outs with patience. But, with rising strike out rates throughout baseball, we have seen some writers blame sabermetrics for making hitters too patient and too passive. Apparently, a rumor spread in scouting circles--perhaps because a number of scouts are hostile to Luhnow's methods--that the Astros are instructing hitters not to swing at 3-2 counts. (Luhnow responded that this rumor is incorrect.) As nonsensical as the question may seem, some people seem to draw a connection between the Astros' sabermetric inclination toward hitter patience and the team's high strike out rate.
The data would suggest a "no" answer to this question. The Astros may want more patience, but their hitters have not been patient. The Astros are ranked 11th out of the 15 AL teams in pitches/PA. The Astros lead the AL in swinging strike percentage and percentage of balls swung at, and are approximately league average in strikes looking and strike outs looking. The Astros have the third highest rate in the AL of swinging at the first pitch. The data suggests that the Astros are not passive at the plate, and, if anything, are too aggressive. The media's narrative about sabermetrics and passive hitters is not supported by the actions of the hitters on baseball's No. 1 strike out team.
Fangraphs has a couple of recent articles on this subject. David Cameron's "The Myth of the Passive Hitter" systematically responds to the claim that the rising strike outs are due to hitters becoming too passive at the plate. He makes the interesting suggestion that changes in the umpires' calling of the strike zone are to blame.
The Atlanta Braves are not far behind the Astros in strike out rate (Astros: 27%, Braves: 25%). That makes me glad, from a selfish perspective, because the media/commentators have focused on the Braves' strike out propensity in recent weeks. I was getting tired of the articles harping on the Astros' record-setting strike out pace. The Fangraphs article, "About the Braves And All Of Their Strike Outs," shows that the Braves have been productive despite the high K rate, and places the strike out issue in perspective. We expected the Astros to strike out a lot, but we hoped for a trade off of more power. Unfortunately, the power has not shown up to the extent we wanted. The Astros are 11th in the AL with an isolated power rate of .152. If the Astros had the same .172 ISO as the Braves, we probably could live with setting the major league strike out record.