His primary research interests are question-answering behavior, intermediation, and the evaluation of information services. His book Understanding Reference Transactions explains the use of hierarchical linear modeling to investigate the factors that contribute to success in responding to reference questions in public libraries. He received the 1997 Methodology Award from the Association for Library and Information Science Education for his application of meta-analysis to evaluation studies of reference service. He earned his Ph.D. from the University of California, Los Angeles.