Advanced stats added to website

A new Advanced Stats page has been added to the website, providing a host of sabermetric-inspired statistics for every season since the league began. Provided below are brief descriptions and motivations for using these over traditional statistics to evaluate player performances. This page is a work in progress, and existing limitations are mentioned with the stat descriptions below.

If anyone reading this article is interested to learn more about any of these stats, I highly recommend A Fan’s Guide to Baseball Analytics: Why WAR, WHIP, wOBA, and Other Advanced Sabermetrics Are Essential to Understanding Modern Baseball by Anthony Castrovince. I thought it was a pretty engaging read for a book all about statistics; plenty of historical examples and “dad jokes” throughout.

Note: Anywhere “lg_” proceeds a statistic, the league-wide average is used. For instance, “lg_OBP” denotes the league-average On-Base Percentage. All other abbreviations used below are consistent with sites like FanGraphs or

Runs Created (RC)

Runs created attempts to estimate the number of runs a hitter contributes to their team, independent of factors outside of their control (ie. whether they are often batting with runners on base, or with productive hitters behind them). While multiple versions of this statistic exist, the RC value displayed on the MABL website uses the “stolen base” version given by Wikipedia as:

In addition to taking into account a batter’s ability to get on-base, and to hit for power (via total bases), this formula accounts for baserunning ability via the stolen base component. Down the road, my hope is to adopt the “technical” version provided on the same Wikipedia page. While grounding into double plays (GIDP), intentional walks (IBB), and sacrifice types (sacb vs sacf) have not been tracked in the database which holds the stats that appear on the MABL website, those events could be mined from stats submissions since the league began using iScore (starting with the Spring 2018 season) and be applied for a slightly more comprehensive calculation of a player’s offensive contributions. Of the stats described here, runs created is the value that I feel does the best job ranking offensive performance.

Weighted On-Base Average (wOBA)

Weighted On-Base Average is a rate statistic which attempts to credit a hitter for the value of each outcome (single, double, etc) rather than treating all hits or times on base equally. wOBA is on the same scale as On-Base Percentage (OBP), but aims to offer a better representation of offensive value than traditional stats. While the weights associated with different events should change depending on the run environment, the formula that has been used for the wOBA (and dependent statistics) reported on the MABL website is given on FanGraphs as:

A major caveat is required here; the “run environment” of a Major League Baseball game is quite different than that of the MABL. Home runs and extra-base hits are far less prevalent in our games, while stolen bases are a much more common occurance — thus the weights assigned to different outcomes in the formula above (taken from the 2013 MLB season) probably require some adjustment to accurately scale to runs produced in an MABL game. Diving into this calculation is beyond the scope of this article, and beyond the time I have had available thus far, but perhaps one day I (or someone else) will take a closer look at these weights and determine how they should be adjusted for our style of baseball.

Weighted Runs Above Average (wRAA)

Weighted Runs Above Average estimates the number of runs a player contributes to his team on offense compared to a league-average player. A wRAA of 0 is league-average, so a positive wRAA denotes above-average performance, while a negative wRAA denotes below-average performance. wRAA is a counting stat (as opposed to a rate stat), so players accumulate more (or fewer) runs as they play more games. Given by FanGraphs, wRAA is calculated by:


When calculating Wins Above Replacement (WAR), wRAA is used to account for a player’s offensive contributions. Generally, 10 wRAA is approximately equal to +1 WAR. It’s worth mentioning, that since the wRAA calculation used on the MABL site depends on wOBA, the caveat given above should be considered here as well.

Weighted Runs Created (wRC)

Weighted Runs Created is considered an improved version of the Runs Created statistic, which also attempts to quantify a player’s total offensive value measured in terms of runs. The wRC statistic depends on wOBA, as defined by FanGraphs as:

The same caveats that apply to wOBA as reported on the MABL website are in effect here, which is why I would more strongly endorse the simplified RC version of the statistic for the time being.

Weighted Runs Created Plus (wRC+)

Weighted Runs Created Plus scales a player’s wRC so that the league average for a given season is 100.

For example, a 125 wRC+ means that a player created 25% more runs than a league average hitter would have in the same number of plate appearances. Ultimately, wRC+ should take field differences into account (for now it does not). As touched on by this MABL Instagram post from July 2022, some of the fields that we play on are more hitter-friendly than others, and as described in the wRC+ section of the wRC FanGraphs page given above, wRC+ should take this into account.

Batting Average on Balls in Play (BABIP)

Batting Average on Balls in Play is given on both the hitting and pitching sections of the MABL Advanced Stats page. The formula for BABIP is:

For now, home runs have been treated as hits (traditionally the MABL hasn’t tracked home runs allowed for pitchers, though this information can also be pulled from past iScore submissions). At the professional level, BABIP is fairly consistent from season to season, and even player to player. A batter with a higher than average BABIP is often considered lucky, with the expectation that they will regress to league average given more opportunities. Conversely, a pitcher with an abnormal BABIP is generally viewed as the beneficiary (or victim) of lucky (or unlucky) breaks that should ultimately even themselves out. In the MABL, my feeling is more significant differences in skill level and less consistent defensive coverage contribute to real differences in BABIP from player to player. Someone who is very adept at hitting line drives is likely to have a very good BABIP, while a pitcher who overpowers many of the hitters he faces — leading to a lot of weak contact when contact is made — will have a low BABIP.

Isolated Power (ISO)

Isolated Power describes a batter’s ability to hit for power, given by


While Slugging Percentage (SLG) is significantly influenced by Batting Average (AVG), ISO removes this dependence and indicates the raw power a player has.

Batting Average (BA), On-Base Percentage (OBP), Slugging Percentage (SLG)

Batting average, on-base percentage, and slugging percentage are tradition stats given here for the sake of completeness. The other “advanced” stats described on this page attempt to overcome shortcomings in each of these metrics for evaluating player performance.

On-Base Plus Slugging (OPS)

On-Base Plus Slugging is a rudimentary attempt (in terms of sabermetrics) at quantifying a player’s offensive production in one number. It accounts for a player’s ability to get on base (via OBP) and to hit for power (via SLG) and is determined by combining these quantities:

A shortcoming of OPS is that is considers OBP and SLG as equivalent contributions to offensive production, while in reality OBP is 1.8 times as valuable as SLG. This relative importance is accounted for in wOBA, but OPS does offer the benefits that it is simple to understand and to calculate, and is more encompassing than BA, OBP, or SLG on their own.

Adjusted On-Base Plus Slugging (OPS+)

Adjusted On-Base Plus Slugging scales OPS values to the league average, similarly to wRC+ as described above. While park factors are not currently considered in the OPS+ reported on the MABL website, ultimately the hope is that will also be accounted for with values updated accordingly.

Strikeout Rate (K%)

For either hitters or pitchers, the percentage of plate appearances (or batters faced) that result in a strikeout.


Walk Rate (BB%)

For either hitters or pitchers, the percentage of plate appearances (or batters faced) that result in a walk.


Earned Run Average (ERA)

Perhaps the most widely used measure of a pitcher’s performance is earned run average: the number of earned runs a pitcher allows per nine innings, given by:

While a pitcher’s ability to prevent runs is paramount, thus suggesting a statistic that describes how well they do just that would be the ultimate measure of a pitcher’s effectiveness, ERA has a few recognized flaws. For instance while defensive mistakes are taken into account (albeit on the whims of the official scorekeeper), great defensive plays are not considered, thus a pitcher with an average defense is at a disadvantage compared to a pitcher with an outstanding defense. Furthermore, ERA does not consider the ability of batters faced, or whether or not a field is more conducive to scoring runs.

Adjusted Earned Run Average (ERA-)

Adjusted ERA addresses some of the shortcomings of ERA, but taking into account park factors and normalizing ERA so that league average ERA- is 100. This makes it easier to compare performances from season to season when the run scoring environments may vary. The formula for ERA- is given by FanGraphs as:

The ERA- values posted on the MABL website do not account for differences in run production from field to field, but ultimately the goal will be to update this so it is accounted for.

Fielding Independent Pitching (FIP)

Fielding Independent Pitching attempts to estimate a pitcher’s run prevention independent of the performance of their defense by considering only outcomes that do not involve defense; strikeouts, walks, hit by pitches, and home runs allowed. FIP uses those statistics and approximates a pitcher’s ERA assuming average outcomes on balls in play, generally providing a better representation of performance than ERA at the Major League level. As provided by FanGraphs, FIP is calculated by:


The FIP constant is used to bring FIP onto the same scale as ERA such that the league average FIP and league average ERA are the same each season. FanGraphs uses FIP (rather than ERA) to determine it’s version of Wins Above Replacement (WAR) for pitchers. But as mentioned previously, a caveat for the FIP values posted on the MABL website is for now, they don’t include home runs allowed as that has not been a stat that the league has tracked for pitchers.

Adjusted FIP (FIP-)

Adjusted FIP scales FIP so that the league average receives a value of 100. Like ERA- and WHIP-, lower than 100 indicates better than average performance, while a FIP- of over 100 indicates worse that average performance. This is a useful way to compare pitcher performances over different seasons or eras of the MABL. FIP- is calculated in the same way as adjusted ERA:

Strikeout-to-Walk Ratio (K/BB)

Strikout-to-Walk ratio gives the number of strikeouts a pitcher records for each walk allowed, given by simply dividing a pitcher’s strikeout total by their walk total.

Opponents Batting Average (OBA)

Opponents’ Batting Average is simply the batting average of batters facing a pitcher, given by:

Walks Plus Hits Divided by Innings Pitched (WHIP)

Walks Plus Hits Divided by Innings Pitched describes how well a pitcher has kept runners off base by describing baserunners per inning.

Adjusted WHIP (WHIP-)

Adjusted WHIP normalizes WHIP so that the league average receives a value of 100. A WHIP- of 50 is 50% better (lower) than the league average, while a WHIP- of 150 is 50% worse (higher) than league average.

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