Should project management be based on theories of economics or production?

According to adherents of lean construction, project management theorists and practitioners, when drawing from the concepts and principles of economics, have neglected the management of production. The consequences of this neglect are said to include poor control (low reliability) of handoffs between design, supply and construction specialists, and a tendency to promote adversarial relationships - reducing value delivered and increasing waste. There is increasing agreement in the construction community that these problems must be solved and that the production perspective must be integrated into project management theory and practice. But how is it best to do so? Is it a matter of supplementing existing project management theory and practice with an additional perspective, or should we start from a conceptualization of projects as temporary production systems? This paper explores the alternative of subordinating the economics-based theory of project management to the theory of production. A recent synthesis of an economics-based project management approach is critically assessed, and an alternative, production-based approach is outlined.