UBR Definition
UBR stands for Ultimate Base Running. Traditionally, base running has only been quantified by stolen bases and caught stealing. With UBR, however, base running can be given a run value, helping highlight which players add (or subtract) value through their running.
The Concept of UBR
It’s not easy to quantify the way any one player runs the bases. Each play in each game is unique, so assigning values to base running events is a challenge.
To get around that challenge, UBR was created as a counting statistic that tracks runs added or subtracted by a player’s performance on the bases.
For any given event in a baseball game, there is a run expectancy that can be referenced. As an example, a single with a runner on third will have a run expectancy close to 1.0, as the runner will score almost every time. On the other hand, a single with a runner on first has an expectancy close to 0, as a runner will rarely score in such a situation.
Knowing what should happen in terms of runs scored, on average, after a given batting event, the performance of each runner can then be evaluated. If a runner is consistently producing more runs on the bases than would be expected given the run expectancy of the situations he has encountered, his base running is above average.
It should be noted that stolen bases and caught stealings are not included in the UBR calculation. Those two statistics are tracked separately as simple counting statistics which are accrued over the course of the season. With UBR, the goal is to track the performance of base runners once the ball is put in play.
Why is UBR Important?
The importance of UBR is found in its ability to capture the value that a player contributes to his team via base running skill. This is something that has traditionally fallen through the cracks, meaning players who are able to create extra runs with their legs would not get the credit they deserve.
As a baseball fan, you already know that players can add value with their running ability, even when they aren’t stealing bases. A perfect example is a player scoring from first on a double, rather than having to stop at third. The player that is able to score on that hit guarantees his team a run, while the runner who stops at third then forces the next batter to drive him in.
Modern baseball statistics are an attempt to capture all of the different ways a player is able to add value to his team. Baserunning might not be the most important skill a player can possess, but ignoring its presence would be a mistake.
Also note, that while UBR is important, players are not able to make a notable impact on the game through base running very often. The difference between a good base runner and an average runner over the course of a season is just a few runs in most cases. Those runs matter, but being skilled on the bases is not as valuable as batting or fielding ability.
How is UBR Calculated?
UBR is not a statistic that you will be able to calculate on your own, as the formula requires calculating each individual base running situation a player encounters for an entire season (or career). Fortunately, running UBR totals can always be located on the FanGraphs leaderboard, under the ‘Advanced’ tab.
The calculation process involves adding or subtracting run value by comparing the expected run output of each individual play to what the runner actually accomplished. Going back to the example from earlier, a player scoring from first on a double would add to his UBR by some amount, depending on the specifics of the situation. On the other hand, if a runner managed to somehow not score from third on a single, that player would see his UBR go down because the run expectancy in that scenario is nearly 1.
For further clarity, some of the other inputs in this statistic include the following –
- Advancing an extra base on a hit or getting thrown out trying to advance
- Advancing on a fly ball
- Runner on first reaching second safely on a grounder to shortstop or third
- Advancing on wild pitches and passed balls
What is a Good UBR?
One of the interesting things about UBR is that it is not always the players with a reputation for being the fastest turn out to be the best base runners. Sure, some of the players on the lists below are known for their sheer footspeed, but others are simply adept at timing the play and picking the right moments to take off for the next base.
For starters, understand that 0 is league-average for UBR. So, any player with a positive UBR is an above-average runner. A score in the 2 – 4 range should be considered very good,and anything beyond 4 will typically rank as one of the best performances in a given season.
The two charts below highlight some of the best base runners in the modern game. The first includes the top-ten UBR scores from the 2018 season, while the second features the best single-season UBR scores from 2008 – 2018.
Top-Ten UBR Scores, 2018 MLB Season
| Player | UBR |
| Brett Gardner | 6.1 |
| Matt Chapman | 5.4 |
| Ender Inciarte | 5.2 |
| Amed Rosario | 4.7 |
| Eddie Rosario | 4.5 |
| Billy Hamilton | 4.4 |
| Christian Yelich | 4.2 |
| Tommy Pham | 4.1 |
| Mallex Smith | 4.1 |
| Jose Ramirez | 4.0 |
Top-Ten Single-Season UBR Scores, 2008 – 2018
| Player | Season | UBR |
| Elvis Andrus | 2010 | 7.5 |
| Elvis Andrus | 2013 | 7.3 |
| Elvis Andrus | 2011 | 7.1 |
| Mookie Betts | 2016 | 6.7 |
| Ian Kinsler | 2014 | 6.7 |
| Jose Ramirez | 2016 | 6.7 |
| Brian Dozier | 2014 | 6.4 |
| Michael Bourn | 2011 | 6.6 |
| Xander Bogaerts | 2017 | 6.3 |
| Ian Kinsler | 2011 | 6.3 |
What are the Problems with UBR?
As with many baseball statistics, UBR is not particularly meaningful in short samples. Looking at a player’s UBR for a couple week’s worth of games, for instance, isn’t going to tell you much about his ability on the basepaths. It’s best to view this statistic over the course of a full season, or even over the course of several seasons, to determine how well any given player performs as a runner.