https://www.census.gov/programs-surveys/metro-micro/about.html defines how the MSAs (metropolitan statistical areas) are designated.
Whether or not you agree with how the MSAs are currently defined, Champaign / Urbana is too small to be in the top 150 by population, while Ann Arbor barely makes it in.
Huntsville is ranked #27.
The methodology for making the ranking is described on the web site with the ranking. Each of the following is given equal (20%) weight:
- % with high school diploma or higher
- % with some college or associates degree or higher
- % with bachelor's degree or higher
- % with graduate or professional degree
- various "Quality of Education & Attainment Gap" measures combined