When a team wins the World Series (or even a game), the winning manager is typically forgiven of all his ‘sins.’ His mistakes, large and small, are relegated to the scrap heap marked, “Here lies the sins of our manager and all managers before him, dutifully forgotten or forgiven by elated and grateful fans and media pundits and critics alike.”
But should they be forgotten or forgiven simply because his team won the game or series? I’m not going to answer that. I suppose that’s up to those fans and the media. What I can say is this: As with many things in life that require a decision or a strategy, the outcome in sports rarely has anything to do with the efficacy of that decision. In baseball, when a manager has a choice between, say, strategy A or strategy B, how it turns out in terms of the immediate outcome of the play or that of the game, has virtually nothing to do with which strategy increased or decreased each team’s win expectancy (their theoretical chance of winning the game, or how often they would win the game if it were played from that point forward an infinite number of times).
Of course, regardless of how much information we have or how good our analysis is, we can’t know with pinpoint accuracy what those win expectancies are; however, with a decent analysis and reasonably accurate and reliable information, we can usually do a pretty good job.
It’s important to understand that the absolute magnitude of those win percentages is not what’s important, but their relative values. For example, if we’re going to evaluate the difference between, say, issuing an intentional walk to player A versus allowing him to hit, it doesn’t matter much how accurate our pitcher projections are or even those of the rest of the lineup, other than the batter who may be walked and the following batter or two. It won’t greatly affect the result we’re looking for – the difference in win expectancy between issuing the IBB or not.
The other thing to keep in mind – and this is particularly important – is that if we find that the win expectancy of one alternative is close to that of another, we can’t be even remotely certain that the strategy with the higher win expectancy is the “better one.” In fact, it is a custom of mine that when I find a small difference in WE I call it a toss-up.
The flip side of that is this: When we find a large difference in WE, even with incomplete information and an imperfect model, there is a very good chance that the alternative that our model says has the higher win expectancy does in fact yield a higher win percentage if we had perfect information and a perfect model.
How small is “close” and how big is “a large difference?” There is no cut-off point above which we can say with certainty that, “Strategy A is better,” or below which we have to conclude, “It’s a toss-up.” It’s not a binary thing. Basically the larger the difference, the more confident we are in our estimate (that one decision is “better” than the other from the standpoint of win expectancy). In addition, the larger the difference, the more confident we are that choosing the “wrong strategy” is a big mistake.
To answer the question of specifically what constitutes a toss-up and what magnitude of difference suggests a big mistake (if the wrong strategy is chosen), the only thing I can offer is this: I’ve been doing simulations and analyses of managerial decisions for over 20 years. I’ve looked at pinch hitting, base running, bunting, relievers, starters, IBB’s, you name it. As a very rough rule of thumb, any difference below .5% in win expectancy could be considered a toss-up, although it depends on the exact nature of the decisions – some have more uncertainty than others. From .5% to 1%, I would consider it a moderate difference with some degree of uncertainty. 1-2% I consider fairly large and I’m usually quite certain that the alternative with the larger WE is indeed the better strategy. Anything over 2% is pretty much a no-brainer – strategy A is much better than strategy B and we are 95% or more certain that that is true and that the true difference is large.
With all that in mind, I want to revisit Game 6 of the World Series. In the top of the 5th inning, the Astros were up 1-0 with runners on second and third, one out, and Justin Verlander, arguably their best starting pitcher (although Morton, McCullers and Keuchel are probably not too far behind, if at all) , due to bat. I’m pretty sure that the Astros manager, Hinch, or anyone else for that matter, didn’t even think twice about whether Verlander was going to bat or not. The “reasoning” I suppose was that he’s only pitched 4 innings, was pitching well, and the Astros were already up 1-0.
Of course, reasoning in “words” like that rarely gets you anywhere in terms of making the “right” decision. The question, at least as a starting point, is, “What is the Astros’ win expectancy with Verlander batting versus with a pinch hitter?” You can argue all you want about how much removing Verlander, burning a pinch hitter, using your bullpen in the 5th, and perhaps damaging Verlander’s ego or affecting the morale of the team, affects the outcome of the game and the one after that (if there is a 7th game) and perhaps even the following season; however, that argument can only be responsibly made in the context of how much win expectancy is lost by letting Verlander hit. As it turns out, that’s relatively easy to find out with a simple game simulator. We know approximately how good or bad of a hitter Verlander is, or at least we can estimate it, and we know the same about a pinch hitter like Gattis, Fisher, or Maybin. It doesn’t even matter how good those estimates are. It’s not going to change the numbers much.
Even without using a simulator, we can get a pretty good idea as to the impact of a pinch hitter in that situation: The run expectancy with a typical hitter at the plate is around 1.39 runs. With an automatic out, the run expectancy decreases to .59 runs, a loss of .78 runs or 7.8% in win expectancy. That’s enormous. Now, Verlander is obviously not an automatic out, although he is apparently not a good hitting pitcher, having spent his entire career in the AL prior to a few months ago. If we assume a loss of only .6 runs, we still get a 6% difference in win expectancy between Verlander and a pinch hitter. These are only very rough estimates however, since translating run expectancy to win expectancy depends on the score and inning. The best thing we can do is to run a game simulator.
I did just that, using the approximate offensive line for a poor hitting pitcher, and that of Evan Gattis as pinch hitter. The difference after simulating 100,000 games for each alternative was 6.6%, not too far off from our basic estimate using run expectancies. This is a gigantic difference. I can’t emphasize how large a difference that is. Decisions such as whether to IBB a batter, bunt, replace a batter or pitcher to get a platoon advantage, remove a starter for a reliever, replace a reliever for a better reliever, etc. typically involve differences in win expectancy of 1% or less. As I said earlier, anything greater than 1% is considered significant and anything above 2% is considered large. 6.6% is almost unheard of. About the only time you’ll encounter that kind of difference is exactly in this situation – a pitcher batting versus a pinch hitter, in a close game with runners on base, and especially with 1 or 2 outs, when the consequences of an out are devastating.
To give you an idea of how large a 6.6% win expectancy advantage is, imagine that your manager decided to remove Mike Trout and Joey Votto, perhaps the two best hitters in baseball, from a lineup and replace them with two of the worst hitters in baseball for game 6 of the World Series. How much do you think that would be worth to the opposing team? Well, that’s worth about 6.6%, the same as letting Verlander hit in that spot rather than a pinch hitter. What would you think of a manager who did that?
Now, as I said, there are probably other countervailing reasons for allowing him to hit. At least I hope there were, for Hinch’s and the Astros’ sake. I’m not here to discuss or debate those though. I’m simply here to tell you that I am quite certain that the difference between strategy A and B was enormous – likely on the order of 6-7%. Could those other considerations argue towards giving up that 6.6% at the moment? Again, I won’t discuss that. I’ll leave that up to you to ponder. I will say this, however: If you think that leaving Verlander in the game for another 2-3 innings or so (he ended up pitching another 2 innings) was worth that 6.6%, it’s likely that you’re sadly mistaken.
Let’s say that Verlander is better than any bullpen alternative (or at least the net result, including the extra pressure on the pen for the rest of game 6 and a potential game 7, was that Verlander was the best choice) by ½ run a game. It’s really difficult to argue that it could be much more than that, and if it were up to me, I’d argue that taking him out doesn’t hurt the Astros’ pitching at all. What is the win impact of ½ run a game, for 2.5 innings? Let’s call the average leverage in the 5th-7th innings 1.5 since it was a close game in the 5th. That comes out to 2.1%. So, if letting Verlander pitch through the middle of the 7th inning on the average was better than an alternative reliever by ½ run a game, the impact of removing Verlander for a pinch hitter would be 4.5% rather than 6.6%. 4.5% is still enormous. It’s worth more than the impact of replacing George Springer with Derek Fisher for an entire game because Springer didn’t say, “Good morning” to you – a lot more. Again, I’ll leave it to you to mull the impact of any other countervailing reasons for not removing Verlander.
Before we go, I want to also quickly address Roberts’ decision to walk Springer and pitch to Bregman after Verlander struck out. There were 2 outs, runners in second and third, and the Astros were still up 1-0. Of course Roberts brought in Morrow to pitch to the right-handed Bregman, although Morrow could have pitched to Springer, also a righty. What was the difference in win expectancies between walking and not walking Springer? That is also easy to simulate, although a basic simulator will undervalue the run and win expectancy when the bases are loaded because it’s difficult to pitch in that situation. In any case, the simulator says that not walking Springer is worth around 1.4% in win expectancy. That is considered a pretty large difference, and thus a pretty significant mistake by Roberts, although it was dwarfed by Hinch’s decision to let Verlander bat. It is interesting that one batter earlier Hinch gratuitously handed Roberts 6.6% in win expectancy and then Roberts’ promptly handed him back 1.4%! At least he returned the generosity!
Now, if you asked Hinch what his reasons were for not pinch hitting for Verlander, regardless of his answer – maybe it was a good one and maybe it wasn’t – you would expect that at the very least he must know what the ‘naked’ cost of that decision was. That’s critical to his decision-making process even if he had other good reasons for keeping Verlander in the game. The overall decision cannot be based on those reasons in isolation. It must be made with the knowledge that he has to “make up” the lost 6.6%. If he doesn’t know that, he’s stabbing in the dark. Did he have some idea as to the lost win expectancy in letting his pitcher bat, and how important and significant a number like 6.6% is? I have no idea. The fact that they won game 7 and “all is forgiven” has nothing to do with this discussion though. That I do know.
