Reproducibility of observations on restorative and exodontic needs

The reproducibility of observations on restorative and exodontic needs was studied by re-examination of a sample of secondary school students during a survey of dental status and need for treatment. Reproducibility was analysed by both a quantitative approach using aggregate data and a qualitative approach using tooth by tooth comparison. Reproducibility of all examiners as a collective group for the aggregate data was found to decrease as the frequency of observation of the category of treatment decreased. A lower level of reproducibility was found using the qualitative approach, even for the more frequently observed categories of treatment. Inter-examiner reproducibility was lower than intra-examiner reproducibility. The performance of individual examiners varied greatly. Based on the WHO (1977) definitions of satisfactory reproducibility, most examiners showed satisfactory intra-examiner reproducibility of the aggregate data, but a less satisfactory performance was found for the intra-examiner reproducibility using the qualitative approach, and for inter-examiner reproducibility using both approaches. Individual performance and severity of assessment of need for treatment overall were associated with the number of years since graduation of the examiners. The results indicated a need for strengthened procedures for selection and improved calibration of examiners. Calibration needed to be emphasized in the areas of occlusal lesions and need for one-surface restorations, and for the less frequently observed categories of treatment.