Baseball: Why aren't Stolen Bases Factored into Slugging %?

It might sound odd at first but why isn’t someones cumulative stolen bases for the season factored into Slugging Percentage?

The rationale is this:

Slugging Percentage (SP) = ( (hits+walks)(total base))/(at bats+walks).

This shows helps show how many bases a batter gets per at bat. It’s a more accurate assessment of what you can expect a batter to produce than just batting average.

If it is there to show how many bases a player gets why wouldn’t stolen bases be added to the total bases? If a guy gets a single he is at first and he gets one total base. That makes sense. But what if the guy is a regular Ricky Henderson? If he steals second and then third his one at bat has generated three bases. His batting average should stay the same, but his slugging percentage should, in my opinion, account for the offensive production he has made since getting to first.

Am I missing something or not?


If so, caught stealings should then deduct from your on-base percentage.

A stolen base, unlike a double, can only advance the runner, and not anybody else, so a stolen base is worth less than an extra base would be (tho a “leg” double by someone who is fast would drive in fewer runs than a double by a slower runner).

Walks are not included in slugging percentage. Slugging percentage is a crude measure of power, and necessarily depends upon contact (or an attempt to make contact) with the baseball.

Stolen bases (or attempted stolen bases) are separate events from hits or walks. They cannot occur until after a player has reached base and another player is at bat, so it makes no sense to try to include them in slugging percentage.

A measure of offensive capability that does include hits, walks, and stolen bases is wOBA (weighted onbase average). Check out the link, Fangraphs is a great site.

Well to start with, the “one at bat” did not generate three bases if a player hit a single, then stole two bases; those bases were stolen during someone else’s at bat. Possibly different players.

Slugging percentage is so named because it’s a rough indicator of power, because someone who hits lots of home runs and doubles is a lot more valuable than someone who hits only singles for the same batting average. In the case of a triple it’s as much or more an indicator of speed, though, as is also the case of someone who often bunts his way onto base. You could argue that bunt singles shouldn’t count as a full one base in slugging percentage, either. But it’s generally good enough because few players actually bunt for base hits as a significant number of their hits any more, and a fast guy who hits a lot of triples clearly DOES have power as well.

In terms of measuring a Rickey Henderson type of player who gives extra value because a lot of the time, his walks = he’s on second base and his singles = he’s on third base while the very next batter is still at bat (versus a station-to-station guy), the stat you’d be looking for is something like Runs Created, at least some versions of which factor in stolen bases.

That, or a more traditional Runs Produced stat which counts runs scored along with hitting stats. The idea there is that a good baserunner - of which basestealing is a major factor but not the only one - scores more runs than an average one, by getting into scoring position or taking an extra base with heads-up alertness and quickness. Like Rickey Henderson. A guy who just gets on first base and steals second a lot but doesn’t score any more than if he’d stayed on first base may be more athletic, but not necessarily any more valuable than a guy who’s station to station.

Yes, to some degree that’s a factor of who’s batting behind him to drive the runner in. But that’s also true for any “production” stat like RBI, other than HRs of course.

And who’s slugging percentage would you shift if a batter get’s a single and then has a pinch-runner come in who steals second?

I think you may be a little off on your concept of slugging percentage. It is a measure of how many bases a hitter gets per plate appearance and is used to distinguish power hitters (doubles, occasional triple, home run) versus contact hitters (singles and occassional doubles).

Hitter A: 20 PA with 1 singles, 2 doubles and 1 HR is hitting .200 with a slugging% of .450
Hitter B: 20 PA with 4 singles and 2 doubles is hitting .300 with a slugging% of .400

Thanks guys, I think you hit it on the head with the wOBA. That is what I was looking for. I was looking at slugging as a marker for total bases someone generates per plate appearance as opposed to how how many bases they get per hit.

I get that it is hard to think of adding it but I think it’s not as difficult as it initially looks.
What if a guy is caught stealing? How would that affect it? It wouldn’t. Just like if a guy is thrown out going to second off a hit. It is a single in the books. Same would apply to the stolen base.

A stolen base doesn’t advance a runner…I get that, but it also many times takes a doublee play threat out of an equation and works like a double in that way. You hit the ball…you are on second. Two bases for one at bat.
It just seems that things like stolen bases, bunts, and the other littler parts of the game are undervalued in the stat sheets and slugging % seemed like a place that stolen bases, at least, could fit in. The wOBA one looks like it takes care of that.

Oh and Fatwater is right. I was using the Runs Created formula instead of the Slugging. I was incorrect. Thanks!

You’re welcome.

Let’s move this from General Questions to the Game Room.

samclem, moderator

To add to what’s already been said, I think you’re missing two things:

  1. An actual extra base hit generally has the effect of pushing existing baserunners along. Hitting a double is not as good as hitting a single and stealing a base; it’s BETTER. A double always scores the runner from second and will push the runner at first to third and maybe score him; a stolen base advances no one except the runner. This was already said, but anyway…

  2. Basically, the reason slugging percentage is what it is is because it’s always been that way. Baseball stats don’t actually always make sense. It isn’t really logical to count a batter as having made an out when he reaches on an error, but that’s how they score it; it’s totally illogical but it’s been done that way since the 19th century so they keep doing it that way. I don’t know why sacrifice bunts don’t count against OBP but sac flies do; it’s just the way it is. The way wins are assigned to pitchers is often silly, but the precedent’s there, so it’s there.

Indeed, there’s a lot of stuff baseball doesn’t count at all, and one was named; extra bases taken on hits. If Jim hits a single and Bill advances all the way to third because he’s fast, or gets a good jump and has a presence of mind to remember that the outfielder has a poor arm, that’s an extra base that is every bit as valuable as a stolen base - and yet it is not officially counted at all. There are runners who take dozens of extra bases a year more than other guys, and we don’t even have an official stat for it.

Yeah, that’s why I would personally use a statistic like or based on Runs Scored to measure baserunning. If there were a way to factor in (or factor out) the efficacy of batters behind him, it’d be even better.

I wouldn’t be surprised if serious statheads have spent time thinking about how to distill a measure for “baserunning contribution to offensive value” or somesuch. Ultimately what you really want to know is: if this guy is on first base, with normalized (equivalent) situational hitting behind him, how much more or less likely is he to come around to score versus Joe Average Major Leaguer being on first base?

I just looked at (my usual source for baseball stats) and yes, among the “Advanced Batting” stats is a “Rbaser” rating (Runs From Baserunning) and an all-in “oWAR” rating (Offensive Wins Above Replacement, ex Fielding) that tries to do just that. I haven’t looked at their definitions to see if I’d agree with them or not though.

Interestingly enough the original statistic for “stolen bases” included not only stolen bases but also the extra base a runner might take on a hit when, e.g., scoring from second on a single. Hugh Nicol holds the record for “stolen bases” in one season with 138 in 1887. In fact 16 of the top 25 seasons in SBs were set before 1898 when the modern scoring rule was adopted.

The simplest answer I can think of is that a hit can advance other baserunners, while a stolen base can’t, so the ability to hit with power is worth more than the ability to steal bases. So, for example, a double is worth more than a single and a stolen base because the double will cause runners who are already on base to advance more. A more extreme example is a home run - there is no stolen base equivalent of a homer with men on base.

There are more complex statistical formulae (such as Bill James’ runs created) that factor stolen bases in with total bases (i.e. bases on hits). These generally don’t give as much weight to stolen bases as they do to bases on hits.