That category (EM for short) is one of ten possible geographic "collisions" that exist due to baseball's franchise movement and its incremental expansion.The "West" came into the picture in 1958; the South in 1962 (with the Houston Colt .45s, later the Astros).
As you'll see at the bottom of the chart (at right), the South has insinuated itself into the World Series 20% of the time since 1961...
...but the South has yet to crash through with that tenth category, the "South-South" World Series, a situation partially explained by the fact that the playoff-bound teams from the South have seemingly found themselves in the same league most of the time, making it extremely difficult to bring off the still-elusive "SS" World Series.
And that's why, in case you were wondering, there is no column on the chart for the "SS" series. When it happens, we'll add it.
Since '61, East-Midwest (EM) and East-West (EW) World Series have been the most plentiful, though our breakouts (1961-80 and 1981-2015) show that these two categories have faded into the pack over the past thirty-five years...
...with the East-South (ES) matchup having the highest preponderance (15%) over the past thirty-five years, thanks in large part to the 90s Braves.
If we measure from 1991, when the Braves began their run of World Series appearances (augmented by the Marlins in '97 and '03, the Rays in '08, and the Rangers in '10 and '11), teams from the South have appeared in 44% of the World Series over the past twenty-five years.
The "all-Midwest" (MM) World Series had a bit of a flurry in the 80s, but it then went nearly twenty years before manifesting again in 2006 (Cardinals-Tigers).
Overall, however, Midwest teams are well-represented in the Fall Classic over the past thirty-five years, appearing in 47% of the World Series since 1981 (and, like the South, in 44% since 1991).
Teams from the East have matched the Midwest's performance, appearing in 47% of the World Series since '81.
It's the West that's lagged behind: they have made it to the WS only 36% of the time over that time frame.
We'll sum up the breakouts in an aggregate chart next.
