Amid a weeding project, librarians at a state college suspected GreenGlass's circulation data was inaccurate. This study compared GreenGlass's and Aleph's circulation statistics for a random sample of books. It also determined if GreenGlass's list of books with zero uses included curriculum related works using keyword searching. The study compared GreenGlass's and due date slips' circulation data for curriculum related titles. Some GreenGlass circulation data was erroneous. Additionally, curriculum related books that circulated were on GreenGlass's zero use list. The study's results helped retain pertinent titles and highlighted the inadequacy of relying exclusively on circulation data to weed monographs.