This brings up a different but related question that I've been trying to find an algorithm answer to: If people are willing to give only pairwise comparisons o

This brings up a different but related question that I've been trying to find an algorithm answer to: If people are willing to give only pairwise comparisons of options ("I'd rather do project B instead of A, and C instead of D"), is there a handy algorithm that produces from this a ranked list? You encounter this a lot where people don't know enough to give a prioritization of a full set, but know their little corner of preferences.