The A's are the best story in baseball this year, and it's not even really close. After three consecutive last-place seasons, and after being as far back as 11.5 games less than two months ago, Oakland managed to grab a share of first place after beating Texas on Monday. Even the most optimistic among us last winter couldn't have seen this coming.
There's probably room for multiple novels and movies to explain how this has happened, but at a high level, it's really about three important points. First and most obviously, they've built one of the game's deepest and most dominant bullpens. Second, last year's porous defense (27th-best) has turned into this year's above-average unit (11th), thanks largely to the greatness of Matt Chapman.
Third? Third is that the A's offense proves that all the stories you've heard about baseball in 2018 are true. As a group, they have baseball's highest launch angle. They have baseball's lowest ground ball rate, and baseball's fewest stolen bases. They might be the first team in history to get through a year without a single bunt hit. They're not your traditional offense, and they don't seem to care. This isn't happening by accident.

You've surely heard the term "launch angle" by now, because it -- along with its cousin exit velocity -- was one of the first Statcast™ terms to gain public acceptance when the tracking system came online in 2015. Just do a simple search for "launch angle revolution," and you'll see dozens of results. While that's maybe a little overstated, it's difficult to ignore the fact that ground balls have dropped considerably in each season since 2015, for all sorts of reasons, including usage of data and reaction to shifts.
It's simply a way to put a number on "did you hit the ball in the air or not," in a way that's calculated more directly than a human observer watching and deciding the often imperceptible-difference between a grounder and a liner, or a liner and a fly. The average Major League launch angle this year is 11.7 degrees, the highest of the four years of Statcast™. The A's are at 15 degrees, also the highest of any team in the four years of Statcast™. About two-thirds of home runs are hit between 25 degrees and 35 degrees. It's just a number, like "how hard did you throw this pitch."
There is such a thing as too much launch angle, because popups are bad, and it's not as simple as "more launch angle = success," which we'll get to in a second. But first, let's point out that this is not happening to the A's by coincidence, or because of one extreme player. A dozen Oakland hitters have put at least 50 balls into play, and 11 of them have a higher launch angle than the Major League average. The one who doesn't, outfielder Nick Martini , is off to a nice start, but is also still looking for his first career home run.

How do you get the highest launch angle in the Majors? You collect a ton of players who have above-average launch angles. A great way to avoid the shift is to get the ball off the ground, and the A's have a 39 percent grounder rate, baseball's lowest. The Majors slug .269 on grounders, and .884 on fly balls and line drives. The A's slug .268 on grounders and .902 on fly balls and line drives. Why would they ever want to hit the ball on the ground? They don't, so they don't.
This isn't terribly complicated, really, nor is it actually a new idea for Oakland -- this has been their brand practically forever. While Statcast™ may have brought the term "launch angle" into public view, the A's have known for years that the best way to counter a league of pitchers intent on throwing low in the zone to get grounders was to import a group of hitters with swing paths specifically built towards crushing those pitches.
Remember the last good A's teams, the 2012-14 group of mashers like Brandon Moss, Josh Reddick, and Seth Smith? As one nearly-2,000 word analysis from five years ago pointed out, in regards to the 2013 A's, "Beane's roster was so ground-allergic that only 0.8 percent of their plate appearances were taken by 'ground-ball hitters.' That's not just a concentrated effort to target fly balls. That's a mission statement."
That's exactly right. If we go back over the last 15 seasons of baseball, or 450 team seasons, those 2013 A's currently hold the record for lowest ground ball rate. Last year's A's are second-lowest. The 2014 A's are third lowest. This year's collection is seventh-lowest… just ahead of the 2012 A's. Looking at 2014-'18 combined, the A's have by far the lowest grounder rate, unsurprisingly.

So: We've proven that the A's aren't hitting the ball on the ground, and that they never do. But it's not as simple as "you'll be great if you hit the ball in the air," because the second-highest launch angle team is the Twins, who have baseball's 10th-lowest slugging percentage. It's great to get the ball off the ground, yet it only matters if you can hit it hard when you do so. (This is why no one's after Dee Gordon to up his launch angle, for example.)
The short version of that is: Grounders are usually bad, but hitting the ball in the air doesn't matter if you don't hit it hard in the air.
The A's, of course, do. They have baseball's fourth-best hard-hit rate on fly balls and line drives, just above 50 percent, led mostly by Matt Olson and Khris Davis. (Of 197 hitters with 50 flies and liners this year, Olson's 65.4 percent hard-hit rate is 10th; Davis's 62 percent is 17th.)
That's mostly because of the group of hitters they've collected, of course, but they do more than just hit it hard in the air. The A's are patient, seeing 4.00 pitches per plate appearances, the third-highest in baseball. They're disciplined, with the second-lowest chase rate in baseball behind only the Dodgers, and they have the lowest weakly-hit ball rate in the bigs, ahead of the Red Sox.

None of this makes them the best offense in baseball, because they're not. (By runs per game, they're eighth; by Weighted On-Base Average, they're seventh.) It doesn't mean we give out pennants now based on launch angle, because we don't.
It does mean, however, that the A's have a plan, and they're executing it. Baseball in 2018 is trending towards hitting the ball hard in the air, and having an endlessly deep bullpen. The A's excel at both. We might not have seen this coming, exactly, but this isn't a flukish outcome, either. The 'Swingin' A's' are back. They never really left.