Philip Hobsbaum's rhyme rankings (the larger the number, the stronger the rhyme):
0.75 world/walled, wheels/wells
0.50 bar/fire, hair/got there
W. K. Wimsatt on rhyme:
Wimsatt makes the further point that it is not sounds that rhyme but meanings (or the single-syllabled meaning-nuggets linguists call "morphemes"), which now clash under the cover of likeness. What comes together in the technique we call rhyme are not so much aural signifiers as semantic ones with subtle syntactical identities, for it is Wimsatt's view that "words have no character as rhymes until they become points in a syntactic succession." . . .
In the couplets of Pope, in particular, Wimsatt believes the disparity between the auditory resemblance and the logical divergence--a divergence in both function (syntax) and meaning (root) -- is exploited with unparalleled cleverness. . . . not only words that rhyme, but small parts of larger, countermatching line-segments (clauses and phrases), which come together with a closure in sound that contradicts the contrast in meaning . . .
A Poet's Guide to Poetry (Chicago Guides to Writing, Editing, and Publishing)