The one-shot instruction session is a dominant mode of teaching in academic libraries. While many conference presentations and articles about methods have been shared, there is little consensus about whether a single library session promotes student learning about information literacy topics. This meta-analysis gathers studies that employ quantitative measures of student learning in an attempt to determine if the one-shot is an effective modality for learning. Results indicate the need for a more critical look at the grouping of "one-shot" as a methodology and the need for further robust research on acquisition of student learning outcomes in the one-shot context.