This article examines the relative importance of a variety of factors in influencing hierarchical choice. In our first experiment, we test some implications of Tversky and Sattath's (1979) Hierarchical Elimination Model (HEM) relating to a choice set in which an external constraint has been imposed. (An external constraint changes the decision process by partitioning the brands in a different way than the consumer naturally would.) Our experimental results and the theoretical predictions do not converge. While they agree that external partitions do affect choice probabilities, they differ on the nature of the effect. Next, we run a second experiment to test alternative explanations of our empirical results. Using these results, we propose managerial implications for positioning a #1 and #2 brand.