Summarization: Constructing an Ideal Summary and Evaluating a Student's Summary Using LSA

Summarization means getting the essence of the original document. The summary should be shorter than the original with all minor facts left out and only the main ideas extracted and paraphrased with new words. This work aims to construct an ideal summary from sentences chosen as targets for self-explanations in prior experiments and to use this summary to assess the quality of students' summaries of the same text. This paper briefly describes (1) how ideal summary is systematically constructed based on the target sentences and (2) how LSA is used to measure the similarity between student's summary and ideal summary. Results indicate that target sentences are good indicators for an ideal summary. Comparison against human expert, the initial data shows that the system able to obtain 70-75% agreement in evaluating completeness of student summary and 0.65-0.74 correlation in evaluating quality of student summary.