Dm. Mandy et C. Martinsfilho, A UNIFIED APPROACH TO ASYMPTOTIC EQUIVALENCE OF AITKEN AND FEASIBLE AITKEN INSTRUMENTAL VARIABLES ESTIMATORS, International economic review, 35(4), 1994, pp. 957-979
Asymptotic equivalence of Aitken and feasible Aitken estimators in lin
ear models with nonscalar identity error covariance matrices is usuall
y established in a tedious case-by-case manner. Some general sufficien
t conditions for this equivalence exist, but there are problems with t
he extant conditions. These problems are discussed, and new widely app
licable sufficient conditions are presented and applied to a variety o
f error structures.