UNDER CONSTRUCTION
Here is a 'scorecard' by conference for 1990. This has been constructed using regional results that I discovered on a yellowing piece of paper in my home office.
The reason I first assembled a histogram like this was that regional play is a source of inter-conference and inter-region games unaffected by the vagaries of early-season matchups (some teams have been playing longer than others) and mid-week games. They offer an indicator of the actual strength of the conferences as measured on the field at the end of the season, and could affect how the NCAA views future seedings. There have been years where a lame showing in the regionals seemed to result in one less bid the next year, and vice versa.
Here is the 'histogram' of the success rate for the 1990 NCAA regionals.
------ wins ------
Conference Number 0 1 2 3+ champ my comments
========== ====== === === === === ===== -----------------
Six-Pac 4 1 2 1 strong showing
ACC 4 1 1 2 very weak
SEC 3 3 sweep! (deserved 4)
Big-West 3 1 1 1 mixed
SWC 3 1 1 1 mixed
Sun Belt 3 2 1 not worth 3 bids
Mo-Valley 3 1 2 weak
Trans America 2 1 1 only one belonged
WAC 2 1 1 mixed
Metro 2 1 1 mixed
Big-10 2 1 1 .
ECAC 2 2 .
Southern 1 1 one dominant team
Big-8 1 1 maybe a 2nd bid?
ind(Miami) 1 1 perennial indep.
Atlantic 10 1 1 strong
Pac-10 N 1 1 .
Colonial 1 1 .
EIBL 1 1 .
Big-South 1 1 wasted
Big-East 1 1 wasted
East Coast 1 1 wasted
West Coast 1 1 wasted
Amer. South 1 1 wasted
Southland 1 1 wasted
MAC 1 1 wasted
Ohio Valley 1 1 wasted
Mid-Cont 0 -left out
MEAC 0 -left out
Midwest Coll 0 -left out
SWAC 0 -left out
Play-in series started in 1994.
The Association of Mid-Continent Universities, MEAC, Midwestern Collegiate, and SWAC did not have automatic bids for their champion and did not qualify any teams for at large berths.
ECAC is the old Eastern Collegiate Athletic Conference, consisting of many divisions that are split into many conferences (Metro Atlantic, Northeast, Patriot League, etc) in 1993. EIBL is the old Eastern Intercollegiate Baseball League, made up of the Ivy League and some Patriot League teams.