A methodology for generating structural descriptions of complex digital devices from high-level descriptions and specifications. The methodology uses a systematic technique to map and enforce consistency of the semantics imbedded in the intent of the original, high-level descriptions. The design activity is essentially a series of transformations operating upon various levels of design representations. At each level, the intended meaning (semantics) and formal software manipulations are captured to derive a more detailed level describing hardware meeting the design goals. Important features of the methodology are: capturing the users concepts, intent, specification, descriptions, constraints and trade-offs; architectural partitioning; what-if analysis at a high level; sizing estimation; timing estimation; architectural trade-off; conceptual design with implementation estimation; and timing closure. The methodology includes using estimators, based on data gathered over a number of realized designs, for partitioning and evaluating a design prior to logic synthesis. From the structural description, a physical implementation of the device is readily realized. Techniques for scaling of a model design to provide a scaled design are provided whereby parameters of a model design such as size, circuit complexity, interconnection density, number of I/O connections, etc., can be scaled to produce a scaled version of the design. The scaling techniques employ multi-level hierarchical module replication to produce fully-functional scaled designs which closely match the function of the model design. Test vectors for the scaled designs can be readily obtained by altering test vectors for the model design to account for the replicated modules.