Interexaminer agreement dental caries epidemiological surveys: the importance of disease prevalence in the sample.

OBJECTIVE: To identify desirable characteristics, including different sample sizes and dental caries prevalences, in virtual samples that allow, at the same time, higher values of general agreement percentage (GPA) and Kappa coefficient (kappa), under a low confidence interval (CI), in reproducibility studies. METHOD: A total of 384 statistical simulations of inter-examiner calibration, varying sample size (12, 15, 20, 60, 200 and 500 individuals), caries prevalence (30, 50, 60 and 90%) and percentages of positive (PA) and negative (NA) agreement (30, 50, 60 and 90%) were undertaken. GPA and kappa were used to measure reproducibility and define deviation between them. RESULTS: The sample of 60 individuals, under caries prevalence of 50%, PA and NA of 90%, presented a GPA and Kappa values of 90 and 80%, respectively, a relative small confidence interval (95%CI 0.65 - 0.95) and a GPA/Kappa deviation of 10.00. CONCLUSION: A virtual sample of 60 individuals, under caries prevalence of 50%, seems feasible to produce a satisfactory interexaminer agreement at epidemiological conditions. However, epidemiological studies to corroborate or refute this assertion are necessary.