Finding and Exploring Rating Distributions (Technical Report)

Online rated datasets have become a source for large-scale population studies for analysts and a means for end-users to achieve routine tasks such as finding a book club. Existing systems however only provide limited insights into the opinions of different segments of the rater population. In this technical report, we assume that a segment, e.g., $langle${em 18-29 year old males in CA}$rangle$ has a rating distribution in the form of a histogram that aggregates its ratings for a set of items (e.g., {em movies starring Russel Crowe}) and we are interested in comparing its distribution with a given desired input distribution. We use the Earth Moveru0027s Distance ({tt EMD}) to comparing rating distributions and we prove that finding segments whose rating distribution is close to input ones is NP-complete.