Christine Greenhow, J. D. Walker, Dan Donnelly, and Brad Cohen describe the implementation and evaluation of the University of Minnesota's Fair Use Analysis (FUA) tool, an interactive online application intended to educate users and foster defensible fair use practice in accordance with copyright law by guiding users through a robust, fact-specific, four-factor analysis. After examining the FUA tool's ability to improve both student understanding of the four factors involved in fair use analysis and the quality of student reasoning with those factors, Greenhow, Walker, Donnelly, and Cohen suggest that students still find certain aspects of fair use law particularly difficult to comprehend and offer recommendations for educators and administrators seeking to design or disseminate similar tools to promote informed instructional practices. (Contains 4 exhibits.)