Inter-examiner and intra-examiner reproducibility in clinical and radiographic diagnosis.

The first technical report to be published by the FDI considered the principal requirements for controlled clinical trials of caries preventive agents and procedures. This document advocated the use of a simple reproducibility ratio as a measure of variability in caries diagnosis. In accordance with the FDI recommendations available figures from published work on duplicated examinations are presented in terms of this reproducibility ratio. The data refers to intra- and inter-examiner variability with respect to both clinical and radiographic examinations. Reproducibility studies carried out as a pre-calibration investigation and during the baseline examinations of a current clinical trial are also included. Considerable diversity is apparent, the intra- and inter-examiner variation for clinical examinations ranging from 0-13 to 0-61, and for radio-graphic assessments from 0-06 to 0-60. If an acceptable range of reproducibility ratios is to be formulated then this wide variation will have to be taken into account. Ultimately, if examiner variability cannot be maintained within reasonable limits, then the choice of an examiner could be just as important as the choice of the test substance.