Attending a baseball game is — by the accounting of time, money and proximity — the most invested a fan can be in their team. In other ways, though, showing up to an MLB contest in person can leave fans with a poorer idea of what’s going on. The ballpark is a singularly terrific venue to meet up with friends, bask in sunny summer days and sample fried foods, but from most vantage points, it’s a pretty terrible place to distinguish between a slider and a cutter or pick up on the context of a player’s season.

Now, you don’t need a TV broadcast’s worth of information to enjoy the game playing out in front of you, but most fans want some guidance as to what’s happening and what they should expect from the main characters in play at any given moment. Thus, the scoreboard.

From hand-operated lineups and scores to instant, digitized velocity readings, the suite of in-stadium offerings has advanced rather noticeably in recent years. Still, there is a balance to be struck in a venue where there isn’t a constant companion to explain the numbers on the board — a push and pull between the stats that say the most about baseball right now and the stats that say something meaningful to the most fans.

For most of baseball history, the stat that has accompanied a hitter’s name wherever it goes has been batting average. But as a player evaluation signal, batting average was bumped out of the catbird’s seat years ago. On-base percentage took precedent after Moneyball, and that revolution accelerated into the contemporary usage of complicated, all-encompassing WAR calculations.

Batting average is being relegated in the ballpark now, too. Stadium scoreboards aren’t making hard pivots to WAR, though. (And really, they shouldn't. WAR is great for summing up full seasons, but it’s not enthralling to track on a day-to-day or plate appearance-to-plate appearance basis.) Instead, another number has increasingly emerged as a middle ground — less short-sighted than batting average, more familiar and tangible than WAR.

That number, in most parks that have made the switch, is OPS. Combining on-base percentage and slugging percentage — literally, it’s on-base plus slugging — this stat cuts much closer to the heart of how baseball actually works today.

Yet in a moment of transition, a vacuum of explanatory power, we can do better, and we should do better for the fans who want to grasp the game. That requires looking back at batting average and what gave it such staying power.

What AVG has that OPS lacks

Batting average, like baseball, dates to the 1800s. The history of its evolution is comically short. MLB’s statistical glossary notes that for one season, in 1887, walks counted as “hits” for the purposes of batting average. That alternative version of the calculation might have saved Joey Votto some headaches about 125 years later, but the original — hits divided by at-bats — proved elegant both for what it measured and for where its bright lines fell. A .300 average was excellent; a .200 average was the worst you could carry alongside any prayer of sticking in the majors. That lower bound even got a name — the Mendoza Line, after Mario Mendoza, an infielder whose career exemplified its power.

The gradients between and beyond those poles weren’t delivered unto the earth as intuitive truths, but they were so baked into the language of the game and eventually wider American culture that they still pack a punch. Saying “he’s a .290 hitter” does not require further explanation.

OPS dates to 1984. The simple amalgamation of on-base and slugging — the two stats that follow batting average in a traditional triple slash line — was asserted as a useful metric in John Thorn and Pete Palmer’s influential book, “The Hidden Game of Baseball,” and it picked up steam as writers and fans cast a wider gaze toward the ways on-base ability and power shape a hitter’s game. At times, it was plainly called “production.” Now, perhaps because of its visually familiar “.###” format, it’s popping up as the statistic of choice for summarizing hitters in ballparks. Just this season, fans have taken notice of the shift in Milwaukee, in Detroit … and sometimes in Toronto.

Through no fault of the statistic itself, however, even the most dedicated fan probably doesn’t have a top-of-the-head reference point for the OPS Mendoza Line equivalent. The best estimate is probably somewhere between .600 and .650 — which might reasonably be dubbed the Maldonado Line after defensively gifted Houston Astros catcher Martin Maldonado — but it’s also just not a reference point. There are certain depths a hitter can’t plumb and hope to remain in the big leagues, but those limits vary based on the rest of a player’s profile, and even that target can move substantially from one season to the next.

It’s complicated. That’s why OPS is an upgrade over batting average in most ways — and why it doesn’t quite resonate on scoreboards.

This season, the New York Mets and Philadelphia Phillies have drawn particular attention to their new displays by installing new physical scoreboards and, in the Mets’ case, seemingly attempting to carry out the important mission of delivering player stats to anyone watching from space. Here’s how that one looks:

And here’s the Phillies’ new look, which takes the interesting path of showing the entire triple slash, along with strikeout and walk rates:

That’s commendable in my view. It provides some traditional footholds as well as more telling information about the shape of a player’s production. What you’ll likely notice about that tweet, though, is the praise for what the display does not include. Earlier in the season, the Phillies had prominently shown wRC+ alongside K% and BB%.

Perhaps predictably, this fan — and apparently a few others, given that the stat seems to have disappeared — bristled. wRC isn’t a “normal” stat. And that fan is largely right, however reflexive their disgust: wRC+ isn’t normalized and doesn’t mean much of anything to most visitors to an MLB stadium in 2023.

The sad part, though? With one sentence of explanation, wRC+ would say more than OPS.

Let’s show fans the way with OPS+

To an unfamiliar eye, the lower case “w” and jumble of letters looks daunting. The important part of wRC+, though, is the plus. That means it is “adjusted” for park effects and the league run environment, scaled to make comparisons simple. Where wRC+ is a FanGraphs statistic crafted using the linear weights of each possible batting event, there’s a roughly equivalent version that uses OPS. It is, of course, OPS+.

Stats such as these are called index stats. They relay a player’s production in relation to MLB average. A hitter with a batting line that matches up to the league-wide 2023 average would be sporting a 100 OPS+. Someone off to a nice start, say Boston Red Sox outfielder Alex Verdugo, has an OPS+ of 130, and you can read that as Verdugo being 30% better than the average MLB hitter. These are rate stats, not cumulative ones, so April brings comical extremes — the Phillies’ Brandon Marsh entered Thursday with a 208 OPS+, or 108% better than average — that sometimes turn out not to be comical at all: Last year, Aaron Judge logged a 212 OPS+ across the full season.

Thinking about a hitter’s stats this way does require a brief second step, but the sport basically demands it at this point. Throughout history, the sport has cycled through states of play. Sometimes the ball is dead. Sometimes it is juiced. Sometimes it flits back and forth multiple times in a decade.

Part of the reason it’s difficult to internalize OPS is that we are no longer under the illusion that stable, clear lines exist. Someone showing a new fan the ropes would be correct in saying that, generally, an .800 OPS is good. But they would also have to acknowledge how wildly different the levels of good have been in just the past few years.

For example, in 2022, the Mets’ Brandon Nimmo logged an .800 OPS in a down offensive environment and difficult ballpark. That was good for a 130 OPS+, and he signed a $162 million contract this offseason. In 2019, the Minnesota Twins’ Eddie Rosario put up an .800 OPS in a record-setting home run environment, which was good for only a 107 OPS+. He hit slightly better the following season … and was non-tendered afterward, with the Twins unwilling to pay him what his home runs would’ve earned in salary arbitration. You could point to defensive value as one differentiating point, but OPS+ goes much further than OPS in explicating that chasm.

In a ballpark, OPS+ has a clear role to play. With just a sliver of screen dedicated to giving the uninitiated their bearings with a simple legend — 100 = park- and era-adjusted MLB average, 110 = 10% better than average — the scoreboard could give people their choice of inquisitive paths. Do they simply want to know if a hitter is good? OPS+ can tell you that. Do they want to understand what good looks like? OPS+ also provides that when paired with the triple slash line, which nearly every scoreboard offers in some form or fashion.

The index stat lives up to its name. It tells you exactly where to look. At this inflection point in baseball history, that’s the best thing a stat can do.

Stat this: OPS+

How is it calculated? Add on-base percentage plus slugging percentage, then scale it to the league average for the desired timeframe and adjust for home park.

Where to find it: Baseball-Reference player pages and leaderboards. FanGraphs uses the similar wRC+ on its player pages and leaderboards.

Weekly stat watch

This might matter: Speaking of remaining conscious of baseball’s eras, we are currently living through an all-time golden age for strikeouts, if you’re inclined toward those. The Atlanta Braves’ Spencer Strider certainly is. Following a pristine start this week in which he flirted with a perfect game, Strider has struck out at least nine batters in nine consecutive starts. That’s a new team record and only two starts away from tying Nolan Ryan for the all-time mark.

Gerrit Cole, Chris Sale and Shane Bieber have all managed streaks just as long or longer since 2018, thus the era’s influence, but Strider is tipping toward a feat that sticks out even in a favorable landscape. So far this season, he’s running a 42.6 K%, which would be a record.

That probably doesn’t: Early-season baseball has to produce tweets, but sometimes, it seems, you really have to dig deep. If you want to develop a strong radar for tweets you can skip, start by training your stat palate on the category of “multi-qualifier” achievements that are turned into nuggets purely by adding situational stipulations that don’t mean much of anything.

Such as this.

Hat tip to Cespedes Family BBQ, who are tracking these misleading nuggets.

Have a question about stats in baseball? Email zach.crizer@yahoosports.com or tweet at @zcrizer.