Here's a quickie for you (and we should never disparage "quickies," especially given the state of the world's "cultural economy"...) to show how things change when an offensive explosion starts to resemble a fallen soufflé.
Fourteen years into "the new century," we can look at the percentages of low run scoring games (those games where the total number of runs for both teams is six or less) and see how the offensive landscape has changed.
The rising line in the single-year chart (at right) shows how much (and how fast) things have changed. When we divide those fourteen twenty-first century years into two seven-year groups (2000-06, 2007-13), we see that each team, on average, has increased from 44 low-scoring games in the first seven years to 51 such games in the second seven seasons. That's a 16% uptick; the chart shows you that we are approaching the percentages that were in place in the 1988-92 time frame.
We can go a bit further, though, and look at the results by team. When we do that, we get an interesting result that tracks with the title of our not-so "quickie." The table at left shows the results by team in low-scoring games, with 2000-06 in yellow, 2007-13 in orange.
The STDEV (standard deviation) for team performance in low-scoring games was cut nearly in half in the 2007-13 time frame, as opposed to what it had been in 2000-06.
The other percentages shown in the chart's rightmost columns measure the change in the number of low-scoring games, and the change in WPCT in those games. For the most part, the teams that have increased their number of low-scoring games in 2007-13 have been contending teams during those years; the key exception--as you might expect, given what you know about the data we present--turns out to be the Kansas City Royals. (In their defense, we can say that they have come a long way from their lowly performance--.410 WPCT--in 2000-06.
The top teams in imprpved WPCT in low-scoring games are not quite as cut-and-dried--only the Tampa Bay Rays seem to have parlayed this particularized improvement into consistent contention. What we need to look at--and it won't be a "quickie"--is to see if improvement in this data subset, whether in single season comparisons or longer combinations, correlates with future improvement. For teams like the Braves, GIants and Cardinals, losing greound in these games has not proven fatal to their ability to contend.
So what's interesting here is mostly the systemic tendency for performance range to narrow in low-scoring games when overall offensive levels decline. We'll push back again at this topic a bit later on...