Top Feeder Rankings (From Publication)
Per the site College Transitions, they have a page on "Top Feeder Rankings (adjusted for undergraduate enrollment)."
I would argue that the adjustment is necessary, as 50 kids from a 1,000 person liberal arts college going to Harvard is much more impressive than 50 kids from a 40,000 person public university. The ranking seems to line up with a former WSJ "Top Feeder Schools" ranking. No surprise to see the same old suspects (Ivy League, NESCAC, etc.). I think the average person might be surprised that small LACs lead to great outcomes as well.
#1 Dartmouth
#2 University of Chicago
#3 Claremont McKenna College
#4 Yale
#5 Williams College
#6 Harvard
#7 Northwestern
#8 Stanford
#9 Duke
#10 Amherst College
#11 Middlebury
#12 Brown
#13 Princeton
#14 Wellesley College
#15 UPenn
#16 Colgate
#17 Swarthmore
#18 Rice
#19 Bowdoin
#20 Cornell
The list goes on to 30 or so schools. Vandy, Tufts, Columbia, Wesleyan, W&L, Colby, Bates all make it later.
If you're interested in the adjusted rankings (adjusted for school size), I found the most recent version of College Transition's book online.
1. UPenn
2. Columbia
3. Harvard
4. UChicago
5. Yale
6. Claremont McKenna
7. Princeton
8. Dartmouth
9. Middlebury
10. Georgetown
11. Amherst
12. Duke
13. Williams
14. Stanford
15. Cornell
16. Washington and Lee
17. Brown
18. Boston College
19. Vanderbilt
20. Colgate