Agglomerative Clustering of Rankings Data, with an Application to Prison Rodeo Events Christopher Zorn † July 3, 2003 Abstract This paper considers the problem of assessing item similarity on the basis of rankings data, that is, data on ordinal outcomes. I discuss a modification to the standard dissimilar- ity measure used in agglomerative clustering which addresses the ordinal nature of ranking data. I then apply this alternative to cluster nine events comprising the Angola, Louisiana prison rodeo. Keywords : Cluster analysis, ordinal data, classification, rankings. † Department of Political Science, Emory University, Atlanta, GA 30322. E-mail address: czorn@emory.edu