This analysis of a previous simulation study of electronic prescribing examined the effect of cognitive load, or demand on working memory, on errors. This study found that physician participants who reported a lower cognitive load were more likely to make errors of omission, suggesting that they were not paying sufficient attention to the task. The authors conclude that errors may arise from a mismatch in allocating cognitive resources (how much attention is paid to a task) and the cognitive requirement needed to safely accomplish that task.