Evidence shows that science graduates often do not have the communication skills they need to meet workplace standards and expectations. One common mode of science communication is the poster. In a review of the literature we show that poster design is historically problematic, and that the guidance provided to students as they create posters for assessment is frequently inconsistent. To address this inconsistency we provide some guiding design principles for posters that are grounded in communication theory and the fundamentals of rhetoric. We also present three nondiscipline-specific example posters with accompanying notes that explain why the posters are examples of poor, average, and excellent poster design. The subject matter for the posters is a fabricated set of experiments on a topic that could not actually be the subject of research. Instructors may use these resources with their students, secure in the knowledge that they do not and will never represent an answer set to an extant assessment item. © 2016 by The International Union of Biochemistry and Molecular Biology, 45(3):249-261, 2017.