It’s perhaps worth considering that some schools’ OOS appeal is primarily regional, while at others it’s more national.
There’s a lot of talk at Wisconsin about “Coasties v. 'Sconnies”, but there aren’t actually that many undergrads from coastal states. In one recent year, 57% of the OOS freshmen at Wisconsin were from immediately adjacent states (Minnesota, Illinois, Iowa, and Michigan), with Minnesota (30%) and Illinois (24%) alone contributing 54%—and because the Minnesotans get tuition reciprocity, they don’t pay a premium to attend. The next largest contributors were coastal. New York and California each supplied 5% of OOS freshmen or 2% of the entering class, followed by New Jersey with 2.5% of OOS freshmen and 1% of the entering class.
Contrast that with Michigan where only 7% of the OOS freshmen came from the immediately adjacent states of Ohio, Indiana, and Wisconsin. That rises to 19% if you add Illinois, which technically borders Michigan somewhere out in the middle of Lake Michigan and in any event is relatively nearby. The largest OOS contributor to Michigan’s freshman class was New York with 15% of OOS freshmen and 7% of the entering class, followed by California with 14% of OOS freshmen and 6% of the class. Illinois was third with 12% of the entering OOS freshmen and 5% of the entering class, followed by New Jersey, Ohio, Maryland, Massachusetts, Connecticut, and Pennsylvania in that order.