Intra-observer variability in the determination of the metacarpal cortical index

Abstract

A single determination of the metacarpal cortical index can be considered accurate to within ±0·036, which is +10 per cent of the usual values of the cortical index in normal bone. Comparison of estimates of the over-all variation in the index (including observer variation) with estimates of the measurement variation indicates that much of over-all variability is due to the measuring process itself, and is therefore unavoidable. Improvement in reproducibility can be obtained by using the average of two independent determinations of the cortical index in place of a single assessment.