A method for efficiently engineering large, complex systems is provided. The method uses a uniquely defined decision model to lead the design effort by structuring and analyzing decision making needs of the people who will use the system before any design efforts can constrain the solution. While other methods may suffice for incremental system developments, i.e., system developments where small improvements over legacy systems are the objective, this method is particularly useful where revolutionary system improvements, or wholly new system developments is the objective.