Measurement error and ANCOVA: Functional and structural relationship approaches.

Discusses a functional and structural relationship approach to analysis of covariance (ANCOVA) with a fallible covariate. Examples of both types of analysis are given for the simple 2-group design. Several cases are discussed and special attention is given to issues of model identifiability. An approximate statistical test based on the functional relationship approach is described. On the basis of Monte Carlo simulation results it is concluded that this testing procedure is to be preferred to the conventional F-test of the ANCOVA null hypothesis