A second interpretation, most notably advanced by Ellen Voorhees,E. M. Voorhees, “The cluster hypothesis revisited,” in SIGIR ’85: Proceedings of the 8th annual international ACM SIGIR conference on Research and development in information retrieval, (New York, NY, USA), pp. 188–196, ACM Press, 1985. focuses on the local relationships between documents. The local interpretation avoids having to model the number or size of clusters in the collection and allow relevance at multiple scales. Methods in this spirit include:
