The best way to test the “100%” claim (short of actually applying for admission & aid) is via the online net price calculators. For a variety of income/asset levels - or just for your own - compare the estimates for any schools that interest you. Below is an example for a family in MD with one child and $80K income:
Estimated Net Price … College
$12507 Swarthmore (“meets full need” college)
$15440 Bates (“meets full need” college)
$16909 Colgate (“meets full need” college)
$17877 F&M (“meets full need” college)
$21216 Dickinson (private, does not claim to cover full need)
$21860 Bennington (private, does not claim to cover full need)
$22433 University of Maryland College Park (in-state public flagship)
$25142 Holy Cross (so-called “meets full need” college)
$27742 Sarah Lawrence (private, does not claim to cover full need)
$31438 University of Massachusetts Amherst (out-of-state public flagship)
$34145 NYU (private, does not claim to cover full need)
source: College Abacus
These results are typical of what I’ve seen for various low and middle income levels.
Typically, net prices for “meets full need” schools vary by a few thousand dollars +/- from an average that is competitive with (often lower than) the in-state flagship cost. Typically it is thousands lower than the cost of private schools that do not make the “full need” claim. Typically, the most selective of the “meets full need” schools are among the ones with the lowest net costs. However, a few so-called “meets full need” schools may be stretching the definition of “full”, at least for some income/asset scenarios.
So in my opinion, the claim to “meet 100% of demonstrated need” should not be blindly accepted …
but it’s (usually) not meaningless, either. For a low/middle income student with good stats, and possibly even an upper middle income student with good stats, most of the ~60 schools that make this claim do seem to comprise a set of colleges offering high quality at relatively affordable net costs.