We've read what Boren listed...

1) fan base 2) size of their programs 3) academics of the institutions...We’ll look at them comprehensively as to which is the best fit. And 4) also we’ll consider geography to a certain degree.

Others have taken a pass at what the first 2 criteria could include or mean for BYU.
http://www.cougarboard.com/board/message.html?id=15305121
I want to take a slightly different approach on looking at these. "Size" could mean stadium/arena size, average attendance, revenue and just AP finishes as shown in the post above. But "size" could mean number of teams you actually field in sports the B12 plays. Or instead of AP top 25 finishes how your athletics as a whole measure nationally as shown below.

Note "Num" below is the number of current B12 teams that participate in that sport sanctioned by the B12.

Expansion candidates with each of the 23 Big 12 Conference sports

Men's Sport	               Num	BYU	Cincy	Uconn	Memphis	UH	USF	UCF
Baseball	                9	Yes	Yes	Yes	Yes	Yes	Yes	Yes
Basketball	               10	Yes	Yes	Yes	Yes	Yes	Yes	Yes
Cross Country	                9	Yes	Yes	Yes	Yes	Yes	Yes	No
Football	               10	Yes	Yes	Yes	Yes	Yes	Yes	Yes
Golf	                       10	Yes	Yes	Yes	Yes	Yes	Yes	Yes
Swimming & Diving	        3	Yes	Yes	Yes	No	No	No	No
Tennis	                        6	Yes	No	Yes	Yes	No	Yes	Yes
Track and Field (Indoor)	9	Yes	Yes	Yes	Yes	Yes	Yes	No
Track and Field (Outdoor)	9	Yes	Yes	Yes	Yes	Yes	Yes	No
Wrestling	               10	No	No	No	No	No	No	No
		                         9	8	9	8	8	8	5
								
Women's Sport	               Num	BYU	Cincy	Uconn	Memphis	UH	USF	UCF
Basketball	                10	Yes	Yes	Yes	Yes	Yes	Yes	Yes
Cross Country	                10	Yes	Yes	Yes	Yes	Yes	Yes	Yes
Equestrian	                 4	No	No	No	No	No	No	No
Golf	                         9	Yes	Yes	No	Yes	Yes	Yes	Yes
Gymnastics	                 4	Yes	No	No	No	No	No	No
Rowing	                         8	No	No	Yes	No	No	No	Yes
Soccer	                         9	Yes	Yes	Yes	Yes	Yes	Yes	Yes
Softball	                 7	Yes	No	Yes	Yes	Yes	Yes	Yes
Swimming & Diving	         5	Yes	Yes	Yes	No	Yes	No	No
Tennis	                        10	Yes	Yes	Yes	Yes	Yes	Yes	Yes
Track and Field (Indoor)	10	Yes	Yes	Yes	Yes	Yes	Yes	Yes
Track and Field (Outdoor)	10	Yes	Yes	Yes	Yes	Yes	Yes	Yes
Volleyball	                 9	Yes	Yes	Yes	Yes	Yes	Yes	Yes
		                        11	9	10	9	10	9	10
								
Combined M/W                            20	17	19	17	18	17	15

Learfield Directors' Cup Standings http://thedirectorscup.com/

Year	  BYU	Cincy	Uconn	Memphis	UH	USF	UCF
2014-15	  48	127	74	164	97	73	86
2013-14	  42	222	57	83	80	93	95
2012-13	  43	173	66	86	142	84	67
2011-12	  43	88	61	120	121	76	55
2010-11	  37	150	44	159	104	86	63
2009-10	  36	116	62	154	111	105	106
2008-09	  47	129	52	111	128	116	90
Avg	  42.3	143.6	59.4	125.3	111.9	90.4	80.3

Perhaps these numbers are why we are hearing so much more about UConn lately.

We know that all schools fans will talk/lobby for inclusion. Fans include homer media...some of which also have some national connections/duties. Some schools are so desperate to get in that they'll even allow coaches/AD's/presidents/BoT to leak their hopeful plans which then get taken as breaking news...

We also know that BYU is pretty tight lipped so we don't get much in the way of the coaches/AD's/president/BoT saying much so more and more talk comes from these other hopeful schools. This does not necessarily mean that chatter is a decision of inclusion/exclusion.

I'm certain that what I've included above and what cougarmeister also put together are probably just scratching the surface of the amount of data that the B12 will receive from their external analysis group. But so far each of the points we are able to dig up put BYU in a strong position when looking at these data points.