This talk was presented as part of the 2nd Biennial Kathleen A Zar Symposium at the University of Chicago. For more about the symposium visit: http://www.lib.uchicago.edu/e/crerar/zar/ The purpose of this presentation is to explore the use of authentic assessment to evaluate learning within the 50 - 90 minute library instruction one-shot classroom. Authentic assessment informs both the learner and the instructor whether learning actually takes place using concrete and observable demonstrations. Authentic assessment shapes all aspects of the teaching and learning experience by requiring instructors to define learning outcomes and to develop clear expectations for the learners' performance and proficiency in advance of instruction. Authentic assessment provides instructors with a reliable feedback loop for assessing the quality of the instruction. Additionally, authentic instruction provides the learner the opportunity to self-assess performance, synthesize, apply new knowledge, and reflect on what they have learned. In the time provided, the presenters will 1) define authentic assessment 2) compare it to more traditional forms of assessment , 3) share 4-5 samples of authentic assessment techniques that can be adapted for use, and 4) present the advantages and challenges of applying authentic assessment in the one-shot classroom. The presenters will focus particularly on the 50-90 one-shot teaching and learning environment where the library faculty member works in collaboration with the classroom faculty member. Participants in this session will leave with a greater appreciation for the value of authentic assessment, the courage to try it, and how to recover gracefully and learn from failure.