It's that good timing that allowed the Royals to outperform every projection and prediction to win 95 games and home-field advantage through the postseason, despite the fact that they allowed 17 more runs than they had in 2014 (when they won 89 games) and 40 more than in 2013 (when they won 86 games). You can see it in the mere fact that an offense that finished last in baseball in walk rate and 23rd in home runs, and was graded as merely average or slightly below by OPS+ and wRC+, scored 73 more runs than it did last year, putting up 4.47 runs per game, baseball's seventh-highest total.
What this is, really, is the probably-random sequencing luck that can explain why some teams outperform or underperform their true skill level. Though they led baseball in clutch hitting, the Royals also had a positive clutch score in pitching as well, making them a clear positive outlier and one of the very few teams to have positive scores on both sides of the ball:
Let's be clear about what we're measuring here. Being the most clutch team is not the same as being the best team in big spots, because that would be, by far, Toronto. But the Blue Jays have been consistently good in pretty much every situation, and so they haven't elevated their game. It's about comparing performance in big spots to regular performance, and there, the Royals have excelled, pushing their OPS from .710 in low-leverage situations to .772 in high-leverage spots.
In fact, the Royals haven't just been 2015's most impressive clutch team. We have data on this running back to 1974, and while the plot gets a lot more crowded, you can see that they still stand out:
Of the 1,168 team seasons included, the 2015 Royals' hitting Clutch score is fourth. (The 2008 Angels, who won 100 games despite having a below-average offense and a run differential more appropriate for an 88-win team, are first. Timing matters.)
While we can show that this has, in fact, happened, it's a little more difficult to explain what they've done to make it happen -- though as you'll see in a second, perhaps that's an explanation in itself. Looking at the Statcast™ numbers, Kansas City didn't actually hit the ball harder as a team with men on base, hitting a nearly identical 88.48 mph when the bases empty and 88.34 mph with men on. Individually, it's all over the place, with Mike Moustakas down a half-mile, Eric Hosmer showing no change, and Lorenzo Cain up 1.6 mph.
But we can see that against elite heat, the Royals really stand out. This isn't a perfect stand-in for "big spots," because flamethrowers like Noah Syndergaard throw hard all the time, but we do know that overall, relievers throw harder than starters do, and relievers are usually who you're facing late in games with men on.
Batting average vs. pitches above 95 mph:
1) KC, .284
2) PIT, .274
3) LAA, .273
Slugging percentage vs. pitches above 95 mph:
1) TOR, .473
2) KC, .436
3) DET, .430
Where the Royals also excel in big spots is in simply putting the ball in play, even moreso than they usually do. Kansas City's non-pitcher strikeout rate of 15.8 percent is easily the lowest in baseball, and that drops to 13.8 percent with men in scoring position. But while it's appealing to make the mental connection there, research has shown there isn't much connection between contact rate and Clutch. Further studies have shown that there's just not a ton of year-to-year relationship, which is to say, it's not something that can be considered a skill.
But the Royals don't need to worry about if that keeps up for 2016. They just need it for a few more weeks. It goes a long way toward explaining why a team that was pretty middle-of-the-pack in hitting and baserunning can have the seventh-most runs in MLB, and get home field in the playoffs. Timing matters, and right now, the Royals have plenty of it on their side.