amount of depth-first behavior in an A∗-framework. This has the potential effect of delaying exploration of the ε-cost plateaus slightly, past the discovery of a solution, but still each planner is ultimately trapped by such plateaus before being able to find really good solutions. Then such tricks are mostly serving to mask the problems of cost-based search
(and ε-cost), as they merely delay failure by just enough that one can imagine that the planner is now effective (because it returns a solution where before it returned none). Using a size-based evaluation function more directly addresses the existence of cost plateaus, and not surprisingly leads to improvement over the equivalent cost-based approach - even with LAMA.