Industry practitioners know that construction is plagued by uncertainties. In their most interesting study, Howell and Ballard (1996, p. 6) describe prevailing methods for managing them in the piping function: "Piping success requires minimizing the extent and effects of uncertainty during fabrication and installation. At present, uncertainty in the timing of deliveries of intermediate products from one continuing activity to another defines the production planning and management problem. Lacking tools to minimize the uncertainty in these flows, managers strive for flexibility so that the project can proceed in the face of erratic deliveries and unexpected problems. On piping extensive projects, they rely on