by Mark Malter
After reading the book, Analyzing Baseball with R, by Max Marchi and Jim Albert, I decided to expand on some of their ideas relating to runs created and put them into an R shiny app .
The Server and UI code are linked at the bottom of the Introduction tab.
I downloaded the Retrosheet play-by-play data for every game played in the 2011-2014 seasons in every park and aggregated every plate appearance by one of the 24 bases/outs states (ranging from nobody on/nobody out to bases loaded/two outs). With Retrosheets data, I wrote code to track the batter, bases, outs, runs scored over remainder of inning, current game score, and inning. I also used the R Lahman package and databases for individual player information. Below is a brief explanation of the function of each tab on the app.
Potential Runs by bases/outs state: Matrix of all 24 possible bases/outs states, both with expected runs over the remainder of an inning, and the probability of scoring at least one run over the remainder of the inning (for late innings of close games). I used this table to analyze several types of plays, as shown below. Notice that, assuming average hitters, the analysis below shows why sacrifice bunts are always a bad idea. The Runs Created stat for a plate appearance is defined as:
end state – start state + runs created on play.
I first became serious about this after watching the last inning of the 2014 world series. Down 3-2 with two outs and nobody on base, Alex Gordon singled to center and advanced to third on a two base error. As Gordon was heading into third base, Giants shortstop Brandon Crawford was taking the relay throw in short left field. Had Gordon been sent home, Crawford would likely have thrown him out at the plate. However, the runs matrix shows only a 26% chance of scoring a run with a man on third and two outs, and with Madison Bumgarner on the mound, it was even less likely that on deck hitter Salvador Perez would be able to drive in Hosmer. So even though sending Gordon would likely have ended the game (and the series), it still may have been the optimal play. This would be similar to hitting 16 vs. a dealer’s ten in Blackjack- you’ll probably lose, but you’re making an optimal play. For equivalency, see the Tag from Third analysis below, as this play would have been equivalent to tagging from third after a catch for the second out.
Runs Created All Regular MLB Players: I filtered out all players with fewer than 400 plate appearances and created an interactive rchart showing each player’s runs potential by runs created. I placed the following filters in the UI: year, innings (1-3, 4-6, 7-extras), run differential at time of at bat (0-1, 2-3, 4+), position, team, bats, age range, and weight. Hovering over a point shows the player and his salary. For example, Mike Trout created 58 runs out of a potential of 332 in 2014. Filtering 2013 for second baseman under the age of 30 and weighing less than 200 pounds, we see Jason Kipnis created 27 runs out of a potential of 300.
Player Runs Table: Same as above, but this shows each player (> 400 plate appearances for the selected season), broken down by each of the eight bases states. For example, in 2014 Jose Abreu created 43.5 runs on a potential of 291, and was most efficient with a runner on second base, where he created 10.3 runs on a potential of only 36.
The following tabs show runs expectancies of various offensive plays from the start state the expected end state, based on the expected Baserunning Success rate in the UI. For each play, I created a graphical as well as a table tab. For the graphical tabs, there is a UI to switch between views of expected runs and scoring probability.
Stolen bases Graphic/Table: For each of fifteen different base stealing situations, I show the start state, end state (based on the UI selected success rate), and the breakeven success rate for the given situation. We see that rather than one generic rule of thumb for breaking even, the situational b/e’s vary widely, ranging from 91% with a runner on second and two outs, to 54% for a double steal with first and second and one out (I assume that any out is the lead runner). Notice though that if only the runner on second attempts to steal, the break even jumps from 54% to 72%.
Tag from Third Graphic/Table: I broke down every situation where a fly ball was caught with a runner on third, where the catch was either the first or second out. I tracked the attempt frequency and success rate for each situation, based on the outs and whether there were trailing runners. Surprisingly, I found that almost every success rate is well over 95%, meaning runners are only tagging when they’re almost certain to score. However, the break evens range from 40% with first and third with two outs (after the catch) to 77% with runners on second and third with one out. I believe this shows a gray area between the b/e and success rates where runners are being far too cautious.
The following tabs show whether a base runner should attempt to advance two bases on a single. Again, of course it depends on the situation.
First to Third Graphic/Table: Here we see that the attempted frequencies are very low, and as expected, lowest on balls hit to left field. However, as with the above tag plays, runners are almost always safe, showing another gray area between attempts and b/e’s. For example, on a single to right field with one out, runners only attempt to advance to third base 42.1% of the time, and are safe 97.3%. If we place the UI Success Rate slider on 0.85, we see that the attempt increases the runs expectancy from 0.87 to 0.99.
Second to Home Graphic/Table: Here we see the old adage, “don’t make the first or second out at the plate”, is not necessarily true. Attempting to score from second on a single depends not only on the outs, but also whether there is a trailing runner. The break evens range from 93% with no outs and no trailing runner on first, to 40% with two outs and no runner on first. Once again, the success rates are almost always higher than the break even rate, showing too much caution.
Sacrifice Bunt Graphic/Table: These tabs show that unless we have a hitter far below average, the sacrifice should never be attempted. For example, in going from a runner on first and no outs to a runner on second with one out, or going from a runner on second with no outs to a runner on third with one out, we drop from 0.85 runs to 0.66 runs and from 1.10 runs to 0.94 runs respectively. Worse, I’m assuming that the bunt is always successful with the lead runner never being thrown out. The only situation where the bunt might be wise is in a late inning and the team is playing for one run after a leadoff double. Getting the runner from second and no outs to third with one out increases the probability of scoring from 0.61 to 0.65, IF the bunt is successful. Even here, it is a poor play if the success rate is less than 90%. The graphic tab allows the user to see how the expected end state changes as the UI success rate slider is altered.
UI code: https://github.com/malter61/retrosheets/blob/master/ui.R
Server code: https://github.com/malter61/retrosheets/blob/master/server.R
Mark Malter is a data scientist currently working for Houghton, Mifflin, Harcourt, as well as the consulting firm Channel Pricing, specializing in building predictive models, cluster analysis, and visualizing data. He is also a sixteen year veteran stock options market-maker at the Chicago Board Options Exchange. He has a BS degree in electrical engineering, an MBA, and is currently working on an MS degree in Predictive Analytics. Mark also spent 14 years as a director and coach of his local youth baseball league.
