A Model-Based Frequency Constraint for Mining Associations from Transaction Data

Mining frequent itemsets is a popular method for finding associated items in databases. For this method, support, the co-occurrence frequency of the items which form an association, is used as the primary indicator of the associations's significance. A single user-specified support threshold is used to decided if associations should be further investigated. Support has some known problems with rare items, favors shorter itemsets and sometimes produces misleading associations. In this paper we develop a novel model-based frequency constraint as an alternative to a single, user-specified minimum support. The constraint utilizes knowledge of the process generating transaction data by applying a simple stochastic mixture model (the NB model) which allows for transaction data's typically highly skewed item frequency distribution. A userspecified precision threshold is used together with the model to find local frequency thresholds for groups of itemsets. Based on the constraint w...

• Type: Journal
• Year: 2008
• Where: CORR
• Authors: Michael Hahsler
• Keywords: CORR 2008, Education, Support Threshold, Transaction Data, User-specified Support Threshold