The Oakland A's currently rank fifth in MLB with 4.53 runs scored per game, and they've tallied 70 runs in their last 10 games alone. They're not doing it with home runs, as even with their recent power surge they're only 10th in the AL in dingers (ninth in June alone). However, as I peruse through the team's stats, there is one area in which they seem to be dominating the rest of the league: plate discipline.
One of the many sets of stats available on Fangraphs is the "plate discipline" stats. Here is a list of several of them, along with how the A's rank among the 30 MLB teams:
Formula: (Swings / Pitches)
A's rank: 30th
In other words: A's swing at fewest pitches of any team
Numbers: A's (43.5%), League average (47.2%), Leader (Brewers, 49.9%)
Formula: (# of pitches on which contact was made / Total swings)
A's rank: 1st
In other words: A's make more contact than anyone when they swing, though since they don't swing much other teams might make more total contact overall
Numbers: A's (82.7%), League average (79.2%), Lowest (Astros, 74.5%)
Formula: (Swings and misses / Total pitches)
A's rank: 30th
In other words: The A's swing and miss less often than anybody. Note that this is not just an inverse of Contact%, because it is taken as a percentage of total pitches rather than total swings. So, in this case, they really swing and miss less than anyone, though that's still aided by the fact that they don't swing as often overall. A swing and a miss doesn't really have any good outcomes for the hitter.
Numbers: A's (7.5%), League average (9.7%), Leader (Astros 12.3%)
Formula: (Swings at pitches outside the strike zone / Total pitches outside the zone)
A's rank: 29th
In other words: The A's chase out of the zone less often than anyone except Cleveland. It should be noted that they are also 30th in Z-Swing%, which is the same thing but for pitches inside the strike zone, so this doesn't mean that they're necessarily laying off the bad pitches in favor of swinging at strikes. Again, they're just swinging less at everything, regardless of whether the pitch is in the zone or not.
Numbers: A's (28.2%), League average (30.8%), Leader (Brewers 35.1%)
Formula: (# of pitches on which contact was made on pitches outside the zone / Total swings on pitches outside the zone)
A's rank: 1st
In other words: When the A's do chase, at least they make contact more often than anyone. Perhaps that means that the pitches they are "chasing" are more often, say, hangers up above the zone, or something just off a corner they can still reach, etc., rather than breaking balls in the dirt for easy whiffs. (That last sentence is my speculation, not a statement I can objectively support.) Note that they also rank 3rd in Z-Contact%, so they're also making contact when they swing at strikes. Basically, regardless of where the pitch is, the A's are the best at only swinging if they can hit it.
Numbers: A's (70.1%), League average (65.3%), Lowest (Cubs, 59.2%)
To tie it all together, the A's see a precisely average number of pitches inside the zone: 45.9%, exactly league average, and tied for 14th among the 30 teams.
And what does all of this fantastic plate discipline do for them? Well, they rank 25th in strikeouts, and if you take the strikeouts as a percentage of total plate appearances (K%) then Oakland ranks 28th (or, third-best). On the other side, they have the 4th-most walks, though that drops to 9th in terms of BB%. Add it all up and they're 4th in walk-to-strikeout rate, at 0.47 (average is 0.38, and the Indians lead at 0.54).
For a team that doesn't hit a ton of homers, this kind of efficient approach is important. The A's need to string together prolonged rallies made up of several hits, because they can't count on a walk and a dinger to take a two-run lead. If your hitters are striking out, though, it's going to be tough to build those rallies, or pressure those defenses, or move those runners up, or bring them in from third base. And by generally waiting for a pitch they can drive, they put themselves in the best position to make solid contact and create a quality batted ball that has a good chance of becoming a hit.
And who leads this charge? I like the SwStr% stat the best out of these, because if you have a team strategy of making a lot of contact then the worst thing you can do is swing and miss. Here are the A's, plus their ranks among the 253 MLB hitters with at least 150 plate appearances:
1. Michael Brantley, Indians, 2.8%
4. Ben Zobrist, 3.4%
10. Eric Sogard, 3.7%
22. Sam Fuld, 4.8%
31. Josh Reddick, 5.4%
42. Stephen Vogt, 5.8%
(Ike Davis, 5.8% in 129 PAs)
81. Billy Burns, 7.7%
86. Billy Butler, 7.9%
107. Marcus Semien, 8.5%
(Max Muncy, 9.6% in 84 PAs)
League average, 9.7%
151. Mark Canha, 10.2%
(Josh Phegley, 11.8% in 105 PAs)
211. Brett Lawrie, 12.8%
253. Jimmy Paredes, Orioles, 17.9%
Almost everyone on the team is better than average in this stat. The only exceptions are Canha, who swings hard for a lot of power; Phegley, who also hits for power but somehow doesn't strike out despite all those misses (only 13.3% of his PAs); and Lawrie, who had never been higher than 8.8% before this season, and who is now red-hot and quickly cutting down on his Ks. And hey, there are Sogard and Fuld, toward the top of the league in avoiding misses -- they aren't good hitters, but perhaps it's not such a surprise that the two of them have come through so many times in the late innings given that you can at least count on them to put the ball in play when you need to make something happen.
I know the example of the 2014 Royals has been beaten to death, but that doesn't make it any less relevant. That team succeeded by swinging a lot, making a lot of contact all over the diamond for a lot of singles and doubles, and running wild all over the basepaths. The A's started with that template, but have expanded on it. They don't swing a lot, but they still make lots of contact for lots of hits (8th-best batting average), and they still run wild -- 10th-most steals at the 2nd-best success rate in MLB. But in addition to all of that, they also draw a lot of walks to add some more baserunners, and they at least have moderate power instead of a complete lack thereof. It's a fantastic combination.
The A's traded away a lot of star hitters last winter and lost a lot of power from their lineup in the process. They replaced those stars with a bunch of decent-but-nondescript hitters, and it was unclear what the game plan was. Well, here it is: Have good at-bats, be aggressive on the pitch(es) you want but patient on the ones you don't, and only swing when you think you can do some damage (but also don't bartonially miss those chances to do damage by being too passive). If the pitcher gives you nothing, then take the walk, but don't generally have that as your goal. You might not always clear the fences when you swing, but you will make the best contact you can and keep the Conga line going around the bases.
And hey, if Zobrist wants to catch fire, and Lawrie wants to follow suit, and Burns wants to become Ichiro, and Phegley wants to turn into Nelson Cruz, then that doesn't hurt either. But even when those hot streaks fade, the plate discipline will keep the lineup chugging.
Epilogue: Interestingly, the A's still rank only 14th in BABIP, and aren't anything special in terms of hitting line drives, making hard contact (Hard% on Fangraphs), avoiding soft contact (Soft%), or avoiding infield popups. Does that disprove any theory about them making better contact because of their discipline? Or is it impressive that a lineup full of Sogards and Fulds and Muncies can reach the middle of the pack in those kinds of stats? I don't know the answer, so I'll let you decide that one.