Base Running Value (BRV)

Introducing Base Running Value 4/18/23

Introducing Base Running Value (BRV)

by Drew Duffy 4/18/23

I have expanded some new thoughts into how to evaluate base running performance and value over the past few days. As with all of my “mock” stats, there are imperfections in everything, though I am merely trying to introduce new ways of thinking in each part of the game. 

In base running, the goal is to advance bases and score runs. This creates a lot of incentive for teams to develop speed on the base-paths. Baseball Reference allows a user to sort through base running events in many different ways. I have interpreted some of these categories as “positive” or “negative”. Let me explain a little bit here…

I have chosen to look at nine different factors while trying to create a singular output number for base running value. Among the metrics I included are:

SB(+), CS(-), OOB1(-), OOB2(-), OOB3(-), OOBHm(-), 1stS3(+), 1stDH(+), 2ndSH(+)

Here are some of the Baseball Reference definitions for each:

SB -- Stolen Bases

CS -- Caught Stealing

OOB1 -- Outs on Base at 1st

Example plays: out advancing on a fly ball, out attempting to reach another base on a hit,

doubled off on a line drive, or out attempting to advance on a wild pitch or passed ball (applicable to all OOB)

OOB2 -- Outs on Base at 2nd

OOB3 -- Outs on Base at 3rd

OOBHm -- Outs on Base at Home

1stS3 -- On First, when a single is hit and runner reaches third or scores

1stDH -- On First, when a double is hit and runner scores

2ndSH -- On Second, when a single is hit and runner scores

You may notice that next to each category I placed a (+/-). This shows how I incorporated each of them into my calculation. Here is an example of what each player’s rows look like:

Player A:

The Calculation places weight on each outcome, closely related to the amount of bases gained above expected in my opinion. For example the coefficients for 1 added base is .2 and -.2 for 1 lost base, if you are a runner on first. But, I penalize players slightly more if they make outs at second, third, and home, since the chances of scoring a run are theoretically increased. Each base increases by .2, so an OOB3 (Out on Base 3, or third base) is -.6 as seen above. 

Where my calculation is still a little lacking is how to reward players for taking “extra bases” more than just awarding them an extra .2. I thought about incorporating XBT% or Extra Base Taken Percentage but I thought that it may be a little redundant, so I will continue working on that. I am happy with the process that I have started here, as it shows that there is more to base running than speed and stolen bases alone. While there is other data out in the world, this is what I felt comfortable relying on and this data was within my means of retrieval. 

I have included the top 10 in BRV from 2022 here:

Mike Petriello of MLB.com tweeted out today the top leaderboards so far for “sprint speed” from Baseball Savant for the 2023 season. This made me wonder about the correlation of my BRV and sprint speed. To gain a greater understanding, I pulled the sprint speed data from 2022 and put it up against my BRV. Below are the results…

As you can see, there is an interesting correlation between sprint speed and BRV that is not necessarily tightly related. I chalk this up to a few things. First, I think that my stat is unfortunately still too context independent, which makes it incredibly difficult to evaluate some types of plays. For instance, if a runner is on second base and there is a hard hit single directly at an outfielder (especially one in front of you) with velocity, it is more difficult to score on that pitch than one that is hit the opposite way. Or what about the implications of outs and game situations? Some third base coaches may hold or send a runner depending on which batter is coming up to bat next or depending on how many outs there are in the inning. This also ties into making a difficult distinction between the impact that the team has on the player’s success. Secondly, effective base running is not all about sheer speed. Anticipation, timing, jumps, and different circumstances all lead to effectiveness on the base-paths. Without being able to quantify this just yet, my BRV should still be taken with a grain of salt.

Again, I still do not have great context in my statistic, but I believe the baseline thinking and execution is there. I will continue to look for more precise and advanced ways of evaluating base running and creating a more comprehensive look that values runners who may not have elite speed, but have the brain to make the right decisions for their team.

Sources:

https://www.baseball-reference.com/leagues/majors/2022-baserunning-batting.shtml

https://twitter.com/mike_petriello/status/1648335088831086592

https://baseballsavant.mlb.com/leaderboard/sprint_speed?min_season=2022&max_season=2022&position=&team=&min=10

 Thank you for reading! As always, feel free to leave any thoughts you may have with me on Twitter @DuffyDigest or duffydigest@gmail.com