From Batting Average to wRC+: A Postseason Primer for the Modern Baseball Fan

From Batting Average to wRC+: A Postseason Primer for the Modern Baseball Fan

By: a Baseball Fan (Go Dodgers!)

It’s that time of year, folks. The leaves are changing, the air is crisp, and the Los Angeles Dodgers are back in the World Series, going for back-to-back titles for the first time since the Yankees did it 20 something years ago. They'll be taking on the Toronto Blue Jays, the team that just won't go down, winning game 7 after being down 2-0 in the ALCS. The energy is palpable, and every single at-bat feels like a life-altering event.

As you dive into the analysis online or even listen to the broadcast, you might notice a shift in the language. No longer is it just about Batting Average (AVG). You’re hearing about OPS, wOBA, and maybe even wRC+. What do these alphabet soups mean, and why is your favorite team's front office obsessed with them?

Think of this as your exhaustive, but not overwhelming, guide to the metrics that actually drive run production—the “real currency” of modern front offices.

--The Old Guard: Simple, Visible, and Flawed--

For decades, the simple Batting Average (AVG) was the gold standard. It was easy to calculate and visible in every newspaper.

What it measures: How often a hitter gets a hit (Formula: Hits ÷ At-Bats).

The problem: AVG ignores two fundamental components of offense: walks and power. The old logic was that “hitters should hit,” and walks were seen as passive. A .300 singles hitter was celebrated, but that average doesn’t distinguish between a single and a home run—both count equally.

--The Great Leap Forward: Accounting for the Walk and the Home Run--

The baseball world realized that getting on base is the foundation of creating runs, and that power is crucial. This led to two key stats emerging, the combination of which still dominates the public conversation.

On-Base Percentage (OBP)

Brilliant sabermetric minds started showing that avoiding outs was key to scoring runs. This led to the rise of OBP.

What it measures: How often a hitter avoids making outs, including walks and hit-by-pitches.

The value: It acknowledges that walks have real offensive value—a critical factor that Batting Average completely misses. This is the foundation of offense, and OBP correlates strongly with runs scored.

Bottom Line: Baseball is a game of outs. The ability to not make an out is the single most important action in run creation, and OBP captures that perfectly.

Slugging Percentage (SLG)

Branch Rickey and Allan Roth (the Dodgers’ pioneering statistician) started measuring power using Slugging Percentage back in the 1940s.

What it measures: It captures power by assigning more weight to extra-base hits (a double gets 2 bases, a triple gets 3, and a home run gets 4).

The value: SLG revealed the true value of power hitters. For example, a .270 hitter with 30 homers often produces far more offense than a .310 singles hitter. A .500 SLG means a player averages half a total base per at-bat—that's elite.

On-Base Plus Slugging (OPS)

The "Moneyball" era of the early 2000s brought OPS into the mainstream, creating the primary shorthand we use today.

Formula: OBP + SLG.

The value: It’s a “rough hybrid metric” combining the ability to get on base with power production. Though crude—it treats OBP and SLG points as equally valuable, which they are not—it correlates surprisingly well with overall offensive output.

Shorthand: OPS is the best one-number summary for a player's total offensive contribution in public discussion. It explains about 90% of team scoring variance across seasons.

--The Modern Age: Weighted Metrics and True Run Value--

OPS is a strong proxy, but it has limitations because it treats all outcomes—hits, walks, and different types of hits—as if they had the same value relationship. A modern front office knows that a walk is worth more than the simple 1-to-1 ratio OPS assigns it against a single.

This is where weighted metrics come in. These metrics assign an empirically derived run value to every single event, from a walk to a home run, based on how much it contributes to run expectancy.

Weighted On-Base Average (wOBA)

Think of wOBA as On-Base Percentage with proper, true accounting.

What it measures: It multiplies each outcome (walk, single, double, etc.) by its TRUE RUN VALUE. Statisticians calculate the exact run expectancy of every event that can happen in a game.

The weighting: Because wOBA accounts for the true value of each outcome, a walk is correctly valued, a double is worth more than twice a single, and a home run has a run value roughly three times that of a single.

The result: Because every event is weighted correctly, wOBA correlates almost perfectly with runs per plate appearance (correlation $\approx 0.98$). It’s on an intuitive scale where a .320 is league average, and .400+ is truly elite.

Bottom Line: wOBA is the most accurate per-plate appearance measure of offensive value that exists.

Weighted Runs Created Plus (wRC+)

wRC+ is the ultimate translation tool for offensive value, taking the accuracy of wOBA and adjusting it for environment.

What it measures: Total offensive value RELATIVE TO LEAGUE AVERAGE and critically, adjusted for park effects (like the difference between hitting at a home run haven and a pitcher's park).

How to read it: It's scaled so that 100 = league average.

* A player with 118 wRC+ is 18% better than league average offensively.
* A player with 80 wRC+ is 20% worse than league average.
* A mark of 160+ wRC+ is MVP-level production.

Illustrative Example: Consider a player with a slash line of .275/.340/.480 and an OPS of .820. That OPS suggests a "pretty good power bat." But if their wRC+ is 118, it confirms they are genuinely above-average run producers, worth about +12 runs on offense—a significant contribution. If you adjust that player for park (say, they play in a tough park like Petco), that number can shift up or down 5–10 points, showing the true environmental impact.

Bottom Line: Because it's park- and era-adjusted, wRC+ is the best metric for comparing hitters across leagues, ballparks, and decades. It is the number the front office uses to compare players across baseball history.

--The Final Takeaway--

You are going to hear OPS a lot in the World Series, and that’s fine; it’s the most practical, strong proxy for total offensive contribution. It’s a great stat.

But if you want to know what the front office is using to analyze the opposing pitcher, value a potential trade, or build the next great Dodgers lineup, it's wOBA and wRC+. They give you the detailed, weighted truth.

As we cheer on the boys in blue (or hate on them, I get it - have at it, then go to Petco park or Angels Stadium and cry your eyes out) (oh wait, no, you can't - those stadiums are locked up for the year. Because, yeah. Season's ended for them.), remember that while a good Batting Average looks nice, it’s the players who maximize their true run value—the wRC+ warriors—that win championships.