The representation of model dynamics, i.e., the time-related interaction among entities in the model, poses the major unresolved problem in simulation model description. This report identifies the issues relevant to the development of model documentation standards. The argument is advanced that documentation and model specification share common objectives and should be coincident. Prior approaches to the generalization of simulation model specification are reviewed with regard to their potential as documentation tools. Their inadequacies stimulate the proposal for the "conical methodology", which emphasizes a top-down, structured model definition phase followed by bottom-up specification. To implement the conical methodology, a simulation model specification and documentation language (SMSDL) is needed. The characteristics of a SMSDL are identified. Recent publications suggest that certain program generator research and the DELTA Project are pursuing objectives similar to those cited for a SMSDL.