What is Pitch Run Value?
In the current sabermetric era, there are hundreds of advanced stats, and new ones are seemingly created every week. To most fans, these metrics seem useless and unimportant. However, there are some advanced stats that can help common fans understand more about what is happening during a game. One of these stats is Run Value on certain pitches. Once explained, this is an easily understandable metric that is great for evaluating both pitchers and hitters.
What is Run Value?
Run value is a stat that has been popularized by Baseball Savant, as it is one of their baseline metrics and is easily accessible on their website. To understand Run Value, it is first important to understand Run Expectancy and Win Expectancy. Every pitch thrown in a baseball game affects the probability of either team winning and the number of runs scored in a game. This can be in a big way or a really small way. Run Expectancy will be highlighted because it is central to Run Value. To first understand run expectancy, it is important to understand the Run Expectancy Matrix.
The matrix above is the number of runs a team is expected to score in each given scenario. With 1 out and a runner on first, a team is expected to score 0.489 runs. With no outs, their scoring jumps to 0.831 runs. However, Run Value is derived from Run Expectancy on a pitch-by-pitch basis, shown in the graph below.
Situation | wOBA | WRAA/PA | Value of Strike | Value of Ball |
3-0 | 0.622 | 0.239 | -0.117 | 0.051 |
3-1 | 0.470 | 0.123 | -0.066 | 0.168 |
2-0 | 0.436 | 0.097 | -0.062 | 0.143 |
3-2 | 0.384 | 0.057 | -0.294 | 0.234 |
1-0 | 0.355 | 0.035 | -0.035 | 0.088 |
2-1 | 0.352 | 0.032 | -0.069 | 0.064 |
0-0 | 0.310 | 0.000 | -0.037 |