Optimal designs for choice experiments with asymmetric attributes

In this paper we establish the form of the optimal design for choice experiments in which attributes need not have the same number of levels for testing main effects only, when there are k attributes, and all choice sets are of size m. We give a construction for optimal and near-optimal designs with small numbers of choice sets. We derive the general form of the determinant of the information matrix for estimating main effects and two-factor interactions and derive the optimal designs for this situation in some special cases.