So, given that one of the teams has a lead, the SH is attempted by the team that is in the lead 62% of the time. I’m not entirely sure of his point.
In The Book, Table 3, I show the “average number of runs scored to the end of the inning”, following each event. It won’t surprise you that the three events that are followed with the FEWEST runs are: CS, K, and other outs. And it won’t surprise you that the most runs are scored following the HR, 3B, 2B. But right there, between reaching on error and getting a single is… the sac bunt. That is, in the PA of the sac bunt, and all PA that follow, the average team scored 1.031 runs.
How is that possible? Well, if we look solely at the base-out situation presented, and regardless of whether the batter bunts or not, we expected 1.058 runs to score. So, this is why we get alot of runs scored in innings when you have a sac bunt: it’s because you happen to have a runner or two already on base!
And in Table 11, we get to the blogger’s point. We see that following a sac bunt, the team wins 62.8% of the time. But before the sac bunt, based on the inning, score, base-out, the chance of winning was 63.8%. Again, we see what the blogger is saying: sac bunts happen to occur when the team already has a good chance of winning.