Complexities of system design are great and often lead designers to be inward looking in their analyses. Knowledge from various fields can be of benefit in designing systems [1]. Management accountants can describe economic effects of delays in closing schedules, psychologist can provide significant insights into the behavioral characteristics of users to complex command syntax, computer performance analysts can provide alternatives to describe and to measure responsiveness of systems. Even in the case of an innovative system design, the designer can employ such approaches to identify incipient problems and create alternatives with increased cost effectiveness. This paper describes how performance metrics can be used effectively to support system design.