Deciphering Advanced Statistics: Part 1

By Patrick Brewersimpsons-sabermetrics

Ever since the release of Moneyball it seems that baseball has only gotten more complex. Baseball used to be as simple as measuring a player’s batting average to know their true talent level. With the advent of the Moneyball strategy, the focus turned from batting average to on base percentage. Over the years it has expanded further than that. Now a batter’s value is measure by WAR, wRC+, WOBA while a pitcher’s value is measured by FIP, WHIP, SIERA, xFIP and a defender is measured by UZR and so on and so forth. More so than ever before baseball has become more complex, and yet understanding of the ins and outs of the game has never been higher or more clear.

For many these new measurements of talent and performance read like a complex foreign language. With this article, I am hoping to explain some of this terminology in more depth and demystify some of these advanced sabermetric concepts for the casual baseball fan. Baseball has advanced quite a bit over the last ten to fifteen years in terms of statistics and has left many casual baseball fans behind.

To begin, let’s start with a more general advanced statistics with the most trendy one being WAR. Basically a player’s WAR value measures Wins Above Replacement or how much better a certain player is than a player who is considered replacement level (or league average). It can also be looked at as a measure of how many wins a player provides to a team with 1 WAR roughly equating to one win provided to a team above replacement. There are several different calculations of WAR based on what website is used. Both Fangraphs (fWAR) and Baseball Reference (rWAR or bWAR) calculate the statistic in different ways and thus arrive at different numbers. WAR is seen as a scale where a player from 0-1 WAR is considered a “scrub,” a player from 1-2 WAR is a role player, a player from 2-3 WAR is a solid starter, 3-4 WAR is considered a good player, 4-5 is considered an all star, 5-6 is considered a superstar, and finally a player over 6 WAR is considered an MVP caliber player. WAR is certainly not a statistic without flaws but still provides a good general estimate of a player’s contributions to his teams win-loss record. This statistic applies to both pitchers and position players although obviously different statistics are used to calculate each value.

In terms of offensive statistics the main ones to focus on are ISO, wRC+, WOBA, WRAA, and BABIP. Let’s start with BABIP as it is the easiest one to understand. Basically BABIP is a measure of a player’s batting average on balls in play. This measures how often a player gets a hit on balls hit in play; therefore it does not include walks, strikeouts, hit batters, catcher interference, sacrifice bunts, and home runs. The general BABIP is around .300 so this statistic is used as a pretty good measure of how lucky a player is getting on balls in play. If a player has a BABIP of near .400 he is clearly getting lucky on balls in play and may be due for some regression.

Next let’s discuss ISO. ISO attempts to quantify a player’s power and how often a player gets extra base hits. The formula is pretty simple and gives home runs a higher weight than triples while triples hold a higher weight than doubles. At its simplest form, ISO can be calculated by taking the slugging percentage of a batter and subtracting from that his batting average to find out his ISO score. Generally an ISO above .150 is considered above average and an ISO near or over .200 is considered great. Generally to get a good measure of a player’s isolated power a good sample size is near a full season of plate appearances.

The next three advanced offensive statistics are a little more advanced and require a little more in-depth calculations. To begin we’ll start with WOBA given it’s importance in calculating both WRAA and wRC/wRC+. WOBA stands for weighted on base average and attempts to provide different values for each outcome (single, double, triple, home run) in order to better quantify a player’s performance when compared to batting average, on base percentage, and runs batted in. This stat is an attempt to measure a player’s general offensive value while providing a more accurate representation of each specific outcome. For perspective a WOBA over .370 is considered great while a WOBA over .400 is considered excellent; Mike Trout currently has a WOBA of .420. 

Next is WRAA. WRAA stands for weighted runs above average and it measures how many offensive runs above average an individual player provides to his team. This stat uses the WOBA value to measure how many runs a player provides to his team above average. A WRAA of zero is considered league average so anything above zero is considered above league average. A WRAA above 20 is considered very good/great while a WRAA over 40 is considered excellent and is near the top of the league. For comparison Mike Trout has a WRAA of 39.5.

Finally is wRC/wRC+. wRC stands for weighted runs created and is an attempt to measure how many runs an individual player contributes to his team. The difference for wRC+ is that this measurement is scaled to a league average of 100 and adjusted for park factors as well as league factors. Every point over 100 represents a player being that percentage point over the league average. Therefore a player with a wRC+ of 125 is 25% better than league average. A wRC+ of 140 is considered great while a score over 160 is considered excellent. For some perspective, Bryce Harper currently has a wRC+ over 200.

In this edition we have deciphered the most important advanced offensive statistics. In the next article, we will focus on advanced pitching statistics and their importance for the modern pitcher.

Patrick Brewer is the Lead National League writer for Call to the Bullpen. You can find him on Twitter @PatrickBrewer93, or join in the conversation @CTBPod, in the comment section below or on our Facebook Page.


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