Investigating the agreement between methods of different precision

TL;DR

This paper proposes a modified Bland-Altman plot that accounts for differing measurement precisions by using inverse-variance weighting, improving the accuracy of method agreement analysis.

Contribution

It introduces a novel modification to the Bland-Altman plot to handle measurement methods with different precisions, reducing false trends.

Findings

The modified plot removes dependence on measurement precision differences.

Simulation results demonstrate improved agreement assessment.

Method effectively distinguishes true measurement dependence from precision effects.

Abstract

Agreement between measurement methods is commonly investigated by a so-called Bland-Altman plot showing if the difference is independent of the size of the measurement. However, such analysis assumes that both methods have the same precision. If not, the plot may show a false trend caused by the difference in precision and not by an actual dependence on the size of the measurement. We suggest a modification of the Bland-Altman plot such that the differences are plotted against an inverse-variance weighted average of the measurements rather than their mean. This study shows that such modification removes the dependence on difference in precision.