Abstract This study investigates the effectiveness of a visual analysis training intervention for teachers. It provides new insight into the influence of data trends on visual analysis and judgments of single-case graphs. Participants were trained in visual analysis and then asked to judge the effectiveness of interventions based on single-case graphs with varying trend and intervention effects. Results partially replicated previous findings, showing that trend effects can lead to false positives in judging intervention effectiveness. However, the training did not significantly improve participants’ ability to differentiate between trend and intervention effects. While training can raise awareness of trends, it may not fully equip individuals to interpret complex data patterns accurately. These findings have implications for researchers and practitioners using single-case designs, emphasizing the need to consider data trends carefully and combine visual analysis with statistical or heuristic approaches.
Bosch et al. (Sat,) studied this question.