In the long run there is a need for a detailed model of behavior at the executive level, a model that deals with these issues rigorously and reliably. Many of the questions asked in this framework, for example, Are the actions taken by the problem solver reasonable? in question A5, and Is the action (or lack of action) taken by the problem solver appropriate or necessary? in Question T2, are highly subjective and can only be answered at this point by making judgment calls. It is hoped that further work will elaborate the bases for such judgments and provide the empirical base from which the more detailed model can be constructed.