  We identify conditions under which a summation over nucleon resonances can
yield, via quark-hadron duality, parton model results for electromagnetic and
neutrino structure functions at large x. While a summation over the lowest even
and odd parity multiplets is sufficient to achieve duality in the symmetric
quark model, a suppression of transitions to specific final states is required
for more realistic cases incorporating SU(6) breaking. We outline several
scenarios consistent with duality, discuss their implications for the high Q^2
behavior of transition form factors, and illustrate how they can expose the
patterns in the flavor-spin dependence of inter-quark forces.
