Towards new measures of information retrieval evaluation.

All of the methods currently used to assess information retrieval (IR) systems have limitations in their ability to measure how well users are able to acquire information. We utilized a new approach to assessing information obtained, based on a short-answer test given to senior medical students. Students took the ten-question test and then searched one of two IR systems on the five questions for which they were least certain of their answer Our results showed that pre-searching scores on the test were low but that searching yielded a high proportion of answers with both systems. These methods are able to measure information obtained, and will be used in subsequent studies to assess differences among IR systems.