Objective: (i) To analyse the consistency of a group of orthodontists' treatment decisions and (ii) to identify factors that may influence this consistency.
Design: Cross-sectional observational study.
Subjects: Ten orthodontists.
Methods: The orthodontists examined 60 case vignettes and recorded their treatment decisions on two separate occasions.
Main measure: Inter- and intra-examiner agreement was evaluated with the Kappa statistic.
Results: The consistency within each orthodontist was moderate. However, between-orthodontist consistency was poor.
Conclusion: It appears that there is marked variation between orthodontists in treatment planning decisions and this may reflect the lack of evidence for the effectiveness of competing treatments.