| Abstract: | This paper reviews and extends some of the known results in the estimation in “errors-in-variables” models, treating the structural and the functional cases on a unified basis. The generalized least-squares method proposed by some previous authors is extended to the case where the error covariance matrix contains an unknown vector parameter. This alleviates the difficulty of multiple roots arising from defining estimators as roots to a set of unbiased estimating equations. An alternative method is also considered for cases with both known and unknown error covariance matrix. The relationship between this method and the usual maximum-likelihood and generalized least-squares approaches is also investigated, and it is shown that in a special case they do not necessarily give identical results in finite samples. Finally, asymptotic results are presented. |
