It represents problems and subproblems, contributing to the solution at different levels of abstraction. As the cases are pieces of DSPL, they do share vocabulary elements. A flat organization of the individual complete cases will suffice, because of the small size of the case library. The solution is hierarchically structured. A case in its original form is hierarchically structured sub-cases.
Structural similarity is used as a tie-breaker.
The cases can't be described in predicates. The cases are used in their original format. It is hard to predict the quality of the result, a design problem-solving system. For a particular system, simulation is necessary. According to Voss' survey, decision support problems are like classification and diagnosis except that there is clearly known goal definition in advance.