Quality, time, and cost tradeoffs in project management decision making

Abstract

This paper presents a mathematical programming model that allows quality to be explicitly considered in project planning and scheduling, while addressing the tradeoffs between quality, time, and cost. A quality function is used to represent the relationships between time, cost, and quality for individual tasks. The initial problem formulation maximizes the minimum quality (weakest link) over all project tasks, subject to bounds on cost and completion time. Using a construction example we show how this model can be adapted to generate quality level curves to illustrate the trade-offs among time, cost, and quality. These level curves can then be used by project managers to make project scheduling decisions that explicitly model and consider quality as well as time and cost, so that better and more appropriate decisions can be made for a particular situation. We also offer some managerial insights for project planning and scheduling that are derived from the analysis through improved understanding of these choices and tradeoffs.