Visual analysis is the primary method of evaluating data in single-subject research. Few studies have evaluated interventions to teach visual analysis skills. The purpose of this study was to evaluate systematic instruction, delivered using computer-based intervention or a recorded lecture, on identifying changes in slope and level in AB graphs. Results indicated that both approaches were significantly more effective than a no-treatment control condition but were not different from each other. We discuss the implications of these results for training and directions for future research.