While the current debate in the evaluation community has concentrated on examining and explicating implications of the choice of methods for evaluating federal programs, the authors of this paper address the challenges faced by the government in the selection of funding mechanisms for supporting program evaluation efforts. The choice of funding mechanism structures the context in which an evaluation is designed and carried out, and in that sense influences the level of specificity involved in describing the requirements of the evaluation. The authors advocate that the type of funding mechanism can limit or enhance the opportunities for the development of theories of and methods for the evaluation of research. The problem addressed is how to develop a set of requirements for an evaluation that takes into account the complexities of contracting. The means for defining requirements in this context is the statement of work (SOW) which is outlined, followed by discussion of the tensions and obstacles in contracting in the context of a government market, a perspective on normative discourse, the range of inquiry purposes along with strategies and difficulties in matching them to contractor capacity and the requirements of the SOW, the tensions and obstacles in the special case of research and development (R&D) in interdisciplinary contexts, and a perspective on management of the complex, ambiguous and unexpected as ways of coping with the demands of contracting.