This paper presents a single scan algorithm for clustering large datasets based on a two phase process which combines two well known clustering methods. The Cobweb algorithm is modified to produce a balanced tree with subclusters at the leaves, and then K-means is applied to the resulting subclusters. The resulting method, Scalable Cobweb, is then compared to a single pass K-means algorithm and standard K-means. The evaluation looks at error as measured by the sum of squared error and vulnerability to the order in which data points are processed.
