A Theory of Information Quality and its Implementation in Systems Engineering

This paper introduces a theory of information quality to explain requirements engineering behavior observed during the systems engineering (SE) process. Requirements are technical statements that inform system design, implementation, and integration. The meaning of requirements information is relevant to the SE problem. The requirements entropy framework (REF) implements the theory and accounts for the meaning of requirements information in terms of its cumulative quality. The requirements quality distribution reflects the cumulative quality and determines the requirements entropy, the number of possibilities, and the additional information needed to reach the desired end state. The desired end state is occupied by requirements having all specified quality attributes. The requirements entropy, uncertainty, and needed information decrease as engineering effort is input into the process. The impact of added, revised, and deleted requirements can be estimated or measured from the change in entropy, uncertainty, or information. Results from computer simulation experiments suggest that the REF is a useful method for monitoring requirements trends, forecasting when the desired end state will be reached, and estimating requirements engineering effort for system development programs.