Beam search is a technique for searching decision trees, particularly where the solution space is vast. The technique involves systematically developing a small number of solutions in parallel so as to attempt to maximize the probability of finding a good solution with minimal search effort. In this paper, we systematically study the performance behaviour of beam search with other heuristic methods for scheduling, and the effects of using different evaluation functions to guide the search. We also develop a new variation of beam search,called filtered beam searchwhich is computationally simple yet produces high quality solutions.