Advanced baseball stats: OPS+, wOBA, wRC, and wRC+

Now that we’re all experts in basic batting stats, let’s move over to the deep end of the pool. Baseball statisticians are forever on the hunt for the perfect numbers to explain a batter’s value, having realized that batting average was too limiting and simplistic a number. We previously looked at batting average, on-base percentage, and slugging percentage when we did our batting primer. With this explainer, we’re going to go onto the more in depth batting stats that strive to give us the best possible representation of batter value: wOBA, wRC, wRC+, and OPS+ which we mentioned briefly in the overview post.

Basically, each stat evolved into the next, so OPS+ made room for wOBA, and from wOBA we have arrived at wRC+, which is currently considered to be one of the best measures of a player’s true offensive value. At the end we’ll mention the new stat, DRC+, which was created just last year by the folks at Baseball Prospectus, but is currently too new to be considered a regular use stat.

Adjusted on-base plus slugging (OPS+)

Since we talked about OPS+ in the batting stat basics article, I’ll just repeat that explanation here.

OPS+ takes a player’s OPS and then adjusts for external factors, like which parks were played in (as some are more hitter friendly than others). OPS+ then is converted onto a scale, where 100 is considered the league average, and the number following it indicates the percentage better than average a player is. For example, Castellanos has an OPS+ of 130 in 2018, indicating his was 30 percent better than league average.

This number is reached by dividing OPS by league OPS, which has been adjusted by park factors, and multiplied by 100.

Weighted on-base average (wOBA)

wOBA is an interesting stat which is used to measure a player’s offensive contributions per plate appearance. Much like how slugging percentage assigns a unique value to extra base hits, wOBA assigns a value to how an individual hitter reaches base, giving a higher value to certain events like home runs. If we want to understand wOBA best, it’s a combination of OBP and SLG, but one that adds additional numerical weight to events like walks and hit by pitches, where OBP only factors in if a player reached base.

It’s a slightly more refined stat, that continues to give importance to what are considered more difficult plays or plays of more value (ie: intentional walks are subtracted from overall walks).

wOBA’s formula is a daunting one:

Courtesy of Wikipedia

As you can see non-intentional walks (NIBB above) are valued the lowest, and home runs are valued the highest. The aim of this stat is to assign a value that resembles batting average (calculated on a 1.000 scale) but gives a truer reflection of a batter’s offensive value. In 2018 Nicholas Castellanos had the Tigers’ highest wOBA with .363.

wOBA should be considered a much more accurate representation of a player’s offensive value that OPS.

Weighted runs created (wRC) and Weighted runs created plus (wRC+)

Of these two stats, if you choose to only learn how to read one, it should be wRC+, which is fast becoming a standard stat used in sports reporting, with enough regularity that you’ll want to be able to recognize its value at a glance. But to understand wRC+ (remember, that plus indicates park factors have been taken into account), we must first understand wRC.

Weighted runs created (wRC) is a measure that attempts to reflect a player’s offensive value and measure it in terms of runs. Sound familiar? It should, as it borrows heavily from the concepts espoused by wOBA, and in fact the numbers for wRC are calculated using wOBA. wRC takes a player’s wOBA, against league wOBA and factors in the number of plate appearances.

Courtesy of FanGraphs

This is where our primer knowledge comes in handy. We’ve already seen with OPS+ and ERA+, that adding park factors across the league allows us to arrive at a more perfect and balanced number to represent success, that is measured out of 100, allowing us to easily see what percentage greater or worse a given player is from league average. Similarly we arrive at weighted runs created (wRC+) by adjusting wRC to account for park factors, which gives us what many consider to the the most comprehensive and complete representation of a player’s true offensive value.

With wRC+ we are now: weighting all on-base events on a value scale, where the more difficult extra base hits have a higher value than walks, and all types of on-base events are included in one formula, rather than dividing on-base percentage (OBP) and slugging percentage (SLG), or simply measuring on-base events against plate appearances like with batting average (BA). We have also included league average wOBA, and league park factors, arriving at the perfect combination of BA, OBP, SLG, OPS+, and wOBA.

Ultimately, by being able to recognize a player’s wOBA value in percentage over 100, you will now be able to recognize at a glance if players are significantly better or worse than league average. For example, only one player on the 2018 Tigers roster had a wRC+ over 100, and that was Nicholas Castellanos with 130, meaning he was 30 percent better than league average.

Deserved runs created plus (DRC+)

If you’re not already overwhelmed by all the wRCs and wOBAs, there’s a new stat that was created by Baseball Prospectus in 2018 called deserved runs created plus (DRC+) which aims to be the batting stat of the future. Whether or not it replace wRC+ as the all-encompassing ideal batting stat remains to be seen, but it’s important to mention it in this list.

Like other plus stats, DRC+ is graded on a 100 scale, with 100 representing league average.

What makes DRC+ different from wOBA and wRC+ is that it takes into account all plate results, and not just results that end in a player on base. While wOBA assigns a value to all events at end in a runner on base, DRC+ also accounts for strikeouts, for a batter hitting into double plays, etc. These negative outcomes are also weighted, similarly to how wOBA weighs positive outcomes. DRC is the total of all these results, which is then factored against league average to arrive at the 100 scale.

Baseball Prospectus believes that by including all the offensive outcomes, positive and negative, we can achieve the most accurate and complete picture of a player’s offensive value.

Nicholas Castellanos, our go-to example for this article, had a DRC+ of 116 in the 2018 season, factoring in things like his 151 strikeouts (7th in the AL), and 21 double plays grounded into (8th in the AL), which obviously knocked off a bit of the shine of his 130 wRC+.

Head on over to the 2018 Tigers FanGraphs page and test out your knew offensive stat prowess. It might give you a newfound appreciation of Niko Goodrum’s season.