  This paper considers the problem of constructing optimal discriminating
experimental designs for competing regression models on the basis of the
T-optimality criterion introduced by Atkinson and Fedorov [Biometrika 62 (1975)
57-70]. T-optimal designs depend on unknown model parameters and it is
demonstrated that these designs are sensitive with respect to misspecification.
As a solution to this problem we propose a Bayesian and standardized maximin
approach to construct robust and efficient discriminating designs on the basis
of the T-optimality criterion. It is shown that the corresponding Bayesian and
standardized maximin optimality criteria are closely related to linear
optimality criteria. For the problem of discriminating between two polynomial
regression models which differ in the degree by two the robust T-optimal
discriminating designs can be found explicitly. The results are illustrated in
several examples.
