Is it worthwhile to sac bunt?
Hey fellow Bucs fans:
For a project in our statistics class, a friend of mine (who is a member at Talking Chop) and I decided to determine if laying down a sacrifice bunt really increased your chances of scoring a run. Our results, in my opinion, were pretty interesting...
(Cutch should probably go ahead and bunt anyways - he's fast enough that it doesn't matter!)
Because there are so many different variables to control for, we looked at one specific condition: when there is a man on first with no outs. (This prevents confounding variables, such as having to compare the efficacy of sac bunting with, for example, men on 1st and 2nd with one out and a man on first with no outs). We looked solely at the American League, so as not to have to deal with the pitcher.
We began by going through every game played in the AL last year, and notating every instance where a man reached first with no outs. We then recorded whether or not that man scored, if he was sac'd over to second, and how many total runs were scored in that inning. 4,728 data points (and a big headache) later, we had all of our data. For the record, of the 4,728 times a man reached first with no outs in the AL last year, he was sac'd over to 2nd 193 times.
Chance of the man on first scoring...
Of the 4,728 times that a man reached first with no outs, he scored 39.36% of the time. We then looked at the effect of the bunt and found out that when the man was not sac'd over, he only scored 39.25% of the time. When he was sac'd to 2nd however, he scored 41.97% of the time. Thus, a sacrifice bunt DOES increase the man on first's chance of scoring. Statistical testing backs up our data to support the conclusion.
Chance of the team scoring...
Although we looked at the chances of the man on first scoring, the team who lays down the bunt is not concerned as much with the man on first scoring, but with anyone scoring. So we next examined the chance that the team scores at all given that they have a man on first with no outs. Essentially, how does the tradeoff of moving a man one base closer, but giving up an out, affect the team's chances of scoring? The chance of scoring at all across the the 4,728 times a man reached first last year was 43.23%. When there was no sac bunt, the chance was 43.24%, and when there was a sac bunt, the chance of a team scoring was 43.01% There is no significant statistical difference between these probabilities. Thus, sacrifice bunt DOES NOT increase a team's chance of scoring a run. The probabilities are virtually identical.
Average runs scored...
Finally, we looked at the average number of runs scored per inning when a man reached first with no outs. Across those 4,728 instances, those teams averaged .9314 runs per inning. When a team sac'd the man over to second, their average runs per inning were .7098. When a team did NOT sac the man over however, they scored an average of .9409 runs per inning. There is significant statistical evidence to support the finding that sacrifice bunting DECREASES the average number of runs scored per inning.
Putting it all together...
So there you have it. In short, sac bunting in the AL is a bad move. You don't increase your chances of scoring any runs in the inning, but you decrease the average number of runs you will score in the inning.
A few limitations...
Like I said, we had to control across all situations, so we only looked at the AL, and what happens with a man on first and no out. We can't really be sure how these conclusions would hold for other bunting situations, and especially for the NL. This study shows that you should never have position players bunt, but as for the pitcher, it is probably still prudent to have him sacrifice, as most pitchers have such a low batting average. We avoided the NL for precisely this reason - the pitcher and his abnormally low BA would confound the study. But as I said, this should hold for all position players.
Thus, unless your batter is Mr. McCutchen up there and he can leg out a single on a bunt anyways, it turns out that having a position player sac bunt is really a sac of:
This is a FanPost and does not necessarily reflect the views of the managing editor (Charlie) or SB Nation. FanPosts are written by Bucs Dugout readers.
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Comments
It doesn't take into consideration
Instances in which teams attempt to sac bunt, but fail to get the runner over.
Tom Tango has a good section in his book about bunting. He discusses the topic more in depth with respect to game theory and uses a more complete set of outcomes including, for example, sac bunt attempts that lead to errors. One of his game theory-related ideas is that even if a sac bunt doesn’t increase your chances of winning, it isn’t a bad idea to do it every once in awhile in order to keep your opponents on their toes (eg. so that they can’t always play their third baseman back and such).
Yeah, definitely
It’s not to say that the sac bunt should be eliminated from the playbook – just that it may not be as beneficial as some managers think it is.
Also – yeah this could definitely be taken a whole lot farther and analyzed all kinds of different ways, but for the purposes of our Stats 101 class this was sufficient. :)
by pittbluedevil on Dec 6, 2009 9:42 PM EST up reply actions
Don’t the extra possibilities (hit, error, DP, FC) increase the odds in favor of the sac bunt? Not to the extent of overcoming the option of not doing it, though, I believe.
by MarkInDallas on Dec 6, 2009 10:14 PM EST up reply actions
Other factors
pertaining to the possible negative consequences of an attempted sac bunt could be used as well, such as a bunted 3rd strike, foul out, double play, forcing the runner out at 2nd, etc. While the extra possibilities you stated could increase the effectiveness of the sac bunt, conversely, accounting for the stats I explained would devalue the bunt even more, since only the figure of 193 times of the bunt actually advancing the runner to second was used in the equation. It would be interesting to see what the results would be with these other variables accounted for. However, really interesting study and explanation.
by TheLizardKing on Dec 7, 2009 12:25 AM EST up reply actions
I don't think that the conclusion you came to
was warranted based upon the work that you did since you didn’t consider the possibility that teams bunt when they have worse hitters coming to the plate after that first man gets on than when they don’t bunt.
For instance if the #2 hitter gets on with the 3, 4 and 5 hitters coming to the plate, not many teams will bunt in that spot and it is an ideal situation for scoring runs. But if, say, the #6 hitter gets on with 7,8 and 9 coming up, maybe it makes sense for the team to bunt in that spot. The fact that they tend to score total fewer runs when they do bunt might then be a function not of the fact that they bunted, but rather of who is coming to the plate after the first guy gets on.
















