MINIMAX REGRET TREATMENT CHOICE WITH INCOMPLETE DATA AND MANY TREATMENTS

This note adds to the recent research project on treatment choice under ambiguity+ I generalize the Manski ~Journal of Econometrics, in press! analysis of minimax regret treatment choice by considering a more general setting and, more importantly, by solving for the treatment rule given finitely many ~as opposed to two! treatments+ The most interesting finding is that with three or more undominated treatments, the minimax regret treatment rule may assign the same treatment to all subjects; thus, the most salient feature of the two-treatment case does not generalize+