The Shifting Sands in the Effects of Source Text Summarizability on Summary Writing

This paper investigated the effects of the properties of source texts on summarization. One hundred and fifty-seven undergraduates were asked to write summaries of one of three extended English texts which were of similar length and readability, but differed in other discoursal features such as vocabulary density and macro-organization. The effects of summarizability were examined from two perspectives: students’ summarization task performance and their perception of such effects as demonstrated in the post-summarization questionnaire and interviews. It was found that source text had significant and relatively larger effects than the summarizers’ language abilities on summarization performance, and such effects were more pronounced on Chinese than English summarization. These findings from the performance data were generally supported by the perception data which shed further light on the dynamics of the summarizability of a source text and its potential effects on performance. The students held that macro-organization, frequency of unfamiliar words, topic familiarity, length of source texts were among the most influential to shape text summarizability. However, the effects of summarizability were rather idiosyncratic. Implications of these findings are discussed in relation to source text selection when designing summarization tasks.