Checklists that focus attention on key variables might allow clinicians to find and fix their mistakes. However, whether this approach can be applied to clinicians of varying degrees of expertise is unclear. Novice and expert clinicians vary in their predominant reasoning processes and in the types of errors they commit. We studied 44 clinicians with a range of electrocardiography (ECG) interpretation expertise: novice, intermediate and expert. Clinicians were asked to interpret 10 ECGs, self-report their predominant reasoning strategy and then check their interpretation with a checklist. We found that clinicians of all levels of expertise were able to use the checklist to find and fix mistakes. However, novice clinicians disproportionately benefited. Interestingly, while clinicians varied in their self-reported reasoning strategy, there was no relationship between reasoning strategy and checklist benefit.