1. A computer implemented method of identifying and ranking preferences regarding a plurality of options, for a group including two or more members, the method comprising: (a) obtaining from one or more data sources, preference information, including partial preference information, for the members, or a subset of the members, wherein the partial preference information may include a set of pairwise comparisons involving one or more of the options; (b) analyzing, by operation of one or more server computers, the pairwise comparisons so as to learn one or more statistical models for inferring and ranking a set of preferences based on the partial preference information; and (c) applying the one or more statistical models so as to identify the set of preferences and rank the options.