The Royals offense is pretty good at scoring runs. The Royals are 6th in the AL in runs scored (behind big slugging teams like Boston, New York, Texas and Toronto) and 2nd in the AL Central behind only Detroit. In fact, the Royals have scored only 17 fewer runs than the Tigers this season when averages to about a tenth of a run per game in difference between the offenses. Based on these numbers, you might think that the Royals offense is almost as good as the Tigers offense. You'd be wrong.
It turns out that for winning baseball games, the distribution of how you score your runs is almost as important as the total number of runs you score. The Royals offense is built around good hitters like Billy Butler, Alex Gordon and Eric Hosmer who generate lots of singles, doubles and walks. The Royals talent matches the Seitzer hitting profile almost perfectly--they hit for average, they show patience at the plate, and they leg out doubles and triples when they pop a ball into the gap. This approach has put them 6th in the league in runs scored despite inexperience and a tiny payroll, but because they don't hit home runs, they need to luck into multiple good outcomes in an inning to plate runners. When the hits clump together, they score runs in bunches, but when lady luck spreads her wealth throughout a game, the Royals struggle to score at all.
Compare the Royals to the Tigers. Both teams have comparable OBPs: the Royals own a .327 OBP, and the Tigers own a .333 OBP. Their team batting averages are essentially identical with just one point in the thousandth column separating the teams. Even the slugging averages aren't as different as you might expect with the Royals slugging .404 and the power-hitting Tigers slugging .416. But a sharp line can be drawn between the types of extra-base hits that the two teams tend toward. The Tigers have hit 30% more HR's than the Royals have (131 to 101) while the Royals have hit almost 20% more doubles and triples than the Tigers have (302 to 255).
Take a look at the run distributions of the two teams to see the effect of this sluggling split:
As you can see from these charts, despite the team scoring averages being separated by only a tenth of a run, the Royals run distribution peaks at 2 runs while the Tigers most frequently score 3 runs. The difference between a 2 run game and a 3 run game is huge. The Royals win 24% of the games in which they score 2 runs, but 37% of their games when they score 3 runs. Scoring that third run multiplies the Royals chances of winning by more than 150%.
You can see the impact of the Royals doubles-based offense not only on the low end of the run distribution, but also on the high end. The Royals have scored 9 or more runs 18 times during which they've scored a total of 189 runs. By contrast, the Tigers have scored 9 or more runs 12 times during which they've scored 119 runs. When the hits bunch together, the Royals really put on a show. And while there's nothing wrong with piling on runs during a game, it turns out that a team's win expectancy when scoring 16 runs isn't much better than when they score 8 runs, so in essence, those 8 extra runs have almost no value to the team. They make a lot of noise in a pythagorean win total, but they don't move the standings at all. And the Royals brand of offense has produced 22 more of these fluffy runs than has the Tigers offense.
Finally, the middle of the graph is where you want the meat of your run distribution to lie. When the Tigers score between 4 and 8 runs, they win more than two thirds of their games. The Tigers offense hits this range 50% of the time while the Royals offense scores between 4 and 8 runs only 39% of the time. And this difference goes a long way toward explaining why the Royals are 18.5 games back in the standings when their run differential suggests they should be only 6 games behind the Tigers.
So while the Royals and Tigers offenses are roughly equally good at scoring runs, it turns out that the Tigers offense is much better for winning baseball games because they concentrate their run distribution between 4 and 8 runs while the Royals offense has a tendency to produce stretches of games where they score 1, 2 or 3 runs followed by a 9+ run outburst.
As long as the Royals continue to shape their offense around OBP and doubles rather than HR's, their run distribution will be sub-optimally weighted at the low and high extremes, and the offense will be better scoring runs than it is a winning games. To win more games, they're going to have to score many more runs across the board so that their inefficient distribution is centered at 3 or 4 runs rather than 2 runs, or they're going to have to hit more home runs to improve the efficiency of their run distribution.