A modelling approach is provided for the analysis of cost-effects of CAD systems. It aims to support strategic management of CAD systems in structural design and construction. The approach is based on the production digraph model of production processes, and the value-added model of information commodities. It has been verified in three case-studies: two concerning the cost-effects in the structural design process at engineering consultants, and one concerning the cost-effects in the production process at a reinforcement-subcontractor. The results of two cases are provided, together with conclusions based on all three case-studies.