The Impact of Frequency on Summarization

Abstract

Most multi-document summarizers utilize term fre-quency related features to determine sentence im-portance. No empirical studies, however, have been carried out to isolate the contribution made by frequency information from that of other features. Here, we examine the impact of frequency on var-ious aspects of summarization and the role of fre-quency in the design of a summarization system. We describe SumBasic, a summarization system that exploits frequency exclusively to create sum-maries. SumBasic outperforms many of the sum-marization systems in DUC 2004, and performs very well in the 2005 MSE evaluation, confirm-ing that frequency alone is a powerful feature in summary creation. We also demonstrate how a frequency-based summarizer can incorporate con-text adjustment in a natural way, and show that this adjustment contributes to the good performance of the summarizer and is sufficient means for duplica-tion removal in multi-document summarization. 1