Abstract
Complex systems operating beyond their expected life or usage can yield scenarios where the current requirements that must be met were “unknown” at the time of their original design. Such “unknown” requirements might be outside the probability distribution expected during the design phase or, more drastically, might not have been predicted. Engineering design researchers have begun exploring how incorporating strategic inefficiencies - in the form of margins - might increase a system's total lifetime value by reducing sensitivity to requirement changes and truncating change propagation. Studying excess, margin beyond what is required for known uncertainties, in a quantitative manner has been particularly challenging as information is needed about how requirements change, how system performance is impacted by requirement changes, and how components are priced. A quantitative study around excess using 20 years of data for desktop computers, video game consoles, and video games is developed. Evidence is provided showing that excess can improve end-user system value when future requirements are unknown. This paper also advances the notion of strategic excess (excess incorporated in a single component), showing as one example that excess RAM would have improved system performance by 14% (on average) for 7% of total system cost. In demonstrating the value of excess, we strengthen the argument that engineers (and end-users) should embrace strategic inefficiencies by considering the implications of their decisions about system architecture and module interfaces.