A design pattern is realized in various forms depending on the context of the applications. There has been intensive research on detecting pattern instances in models and in implementations. However, little work addresses variations of pattern realization. This paper describes an approach for evaluating conformance of pattern variations. This approach uses a divide-and-conquer strategy to evaluate the structural conformance of a UML class diagram to the solution of a design pattern. A design pattern is specified in an extension of the UML that defines the pattern in terms of roles. To demonstrate the approach, we use the Visitor pattern and two case studies of a price calculator and a word processor. We also present a prototype tool that supports the approach. Keywords Design pattern