As a first step of what stands to be a prolonged transition of making the Fielding- and Ballpark-Independent Outcomes (FaBIO) evaluation system applicable to assessing offensive performance I have modified the same files used to process pitcher data for speed and baserunning analyses. Below I will present how most Astros minor league position players of 2015 and/or now rated in terms of these somewhat fielding- and ballpark-independent offensive speed/baserunning analytics.
The first course of action is to filter out the specific events on which a given player's offensive speed and baserunning ability is most likely to show up in game action. There are three general groups of events to review per player: 1. the most relevant of their own plate appearances (esp. infield groundballs and outfield basehits), 2. nonbatted ball sequences while others are at the plate on which the base ahead of them is open for an advance, and 3. batted balls hit by others on which they as a baserunner are capable of taking an extra base or are at risk for being doubled off the bag (select types of outfield basehits, outfield airouts, and infield lineouts).
As such, included in this analysis is every 2015 MiLB plate appearance involving the player for which at least one of the following was true (use CTL + and CTL - to zoom in and out if you insist on reading the fine print):
- As a batter, player hits a non-bunt infield groundball and the defense's initial attempt at an out is not directed at some other runner. Batter is credited with some specific number of runs if they reach via infield single, else he is credited with 0 runs.
- As a batter, player hits an non-bunt infield groundball with 1st base occupied and less than 2 outs. Batter is docked a specific number of runs if the result is a double play ending at first base, else batter is credited with 0 runs.
- As a batter, player gets an outfield non-HR hit. Batter is docked a specific number of runs if retired trying to take an extra base, batter is credited a specific number of runs if they take an extra base when defender throws trying to get a lead runner, else batter is credited with 0 runs (ideally one would also credit a batter who aggressively took an extra bag as a lead runner while drawing a throw, but that determination cannot be made at present via Gameday event text analysis).
- As a runner stationed at 2nd or 1st with the next base unoccupied, player is in position to potentially steal the next base.Runner is credited with a specific number of runs if the next base is stolen successfully, runner is docked a specific number of runs if out trying to steal the next base or is picked off by either the pitcher or catcher, else runner is credited with 0 runs if batter hits a batted ball, strikes out, walks, or is hit by pitch while runner still occupies the same base. If runner advances via some other pathway (wild pitch, passed ball, error, balk, indifference) during the plate appearance, the plate appearance is ignored (unless future baserunning activity that meets any of this or another criteria occurs during the remainder of it).
- As a runner at any base during another batter's plate appearance, runner is out via some other way before the plate appearance is completed or during a non-batted ball ending (walk or strikeout) to it (category includes pickoffs at 3rd or of a blocked trail runner, outs made trying to advance of pitches that momentarily escaped the catcher, and outs trying to stretch an advance made on a steal or wild pitch or passed ball). Runner is docked a certain runs value for the out.
- As a runner stationed at 1st base, another batter hits an outfield single with either 2nd base unoccupied or the runner at 2nd makes it safely to home and not via error. Runner is credited with a specific number of runs if he makes it to 3rd minus the aid of an error, runner is docked a specific number of runs if he is out trying to get to 3rd, else runner is credited with 0 runs.
- As a runner stationed at 2nd base, another batter hits an outfield single. Runner is credited with a specific number of runs if he scores minus the aid of an error, runner is docked a specific number of runs if he is out trying to score, else runner is credited with 0 runs.
- As a runner stationed at 1st base, another batter hits a double. Runner is credited with a specific number of runs if he scores on the play minus the aid of an error, runner is docked a specific number of runs if he is out trying to score, else runner is credited with 0 runs.
- As a lead runner stationed at 2nd or 3rd with less than 2 outs, another batter flies or lines out to an outfielder. Runner is credited with a specific number of runs if he advances to the next base, runner is docked a specific number of runs if he is out trying to take the next base or doubled off the prior base, else runner is credited with 0 runs.
- As a runner stationed at any base with less than 2 outs, another batter lines out to an infielder. Runner is docked a specific number of runs if doubled off the base, else runner is credited 0 runs.
In each instance, the specific amount of nonzero runs credited or docked is determined based on how the inning’s run expectancy per league standards would theoretically rise or fall in line with how the outs and base occupation state changed as a result of or in the absence of the event. In 7 of the 10 scenarios, that value of runs is amplified slightly based on the relative frequency of attempts at that per opportunity in the corresponding ballpark (rewarding the successful advancer more at venues where that advance attempt is rarer by league standards and less so where it is more common).
Each plate appearance that met at least one of the 10 criteria was considered a baserunning opportunity for the player under analysis, and a given plate appearance can feature multiple of the above criteria being true at some point. Effectively all of the runs earned or docked during a plate appearance are summed to yield a runs added outcome for that plate appearance. Completing that process over every qualifying plate appearance yields a total runs added per plate appearance and that value becomes the standard by which the player is judged versus his league reference group of position players. The player is rated based on how many standard deviations he is above or below the league mean of a sample of players who met some minimum number of baserunning opportunities criteria.
The player’s overall Offensive Speed Rating for the season will be expressed on both a percentile basis (that reflects the expected percentage of league peers beaten on the statistic, where 50 is average, 84 is plus, 97 is plus plus, 16 is minus, 3 is minus minus, …) and on a scout scale (where 50 is average, each 10 points up or down is one standard deviation, with 60 plus, 70 plus plus, 40 minus, 30 minus minus, … with the rating rounded to the nearest value that ends with a 0 or 5) for reasons that will become clearer later.