Plan proximity: an enhanced metric for plan stability

Plans executed in the real world have to adapt to the dierences between the expected and the observed state of the environment where is being executed. Plan- ning strategies dealing with this adaptation process can be compared by looking at the plan proximity between the original plan and the plans that these strategies generate to replace it. Plan proximity measures the dierence between these sequential plans and the ex- pected outcome states of these plans. We present ar- guments to support the claim that plan proximity is a more informed metric than plan stability in order to compare planning strategies solving these adaptation to the environment of execution.