Improving Work Flow Reliability

Glenn Ballard1

1Director of Research, Lean Construction Institute, and Lecturer, Construction Engineering and Management Program, Dept. of Civil and Environmental Engineering, University of California at Berkeley, 4536 Fieldbrook Road, Oakland, CA 94619, 510/530-8656, FAX 510/530-2048, [email protected]


Improving work flow reliability is important for the productivity of linked production units, and consequently for project cost and duration. One measure of work flow reliability is PPC, the percentage of planned assignments completed. A proposal is made for experiments to increase PPC. Four actions are proposed and explained. Only the fourth action, underloading resources relative to capacity, is developed in detail in this paper. The potential impacts of improving PPC on project cost and schedule are described.


Capacity, decomposition, design process, explosion, flow, last planner, lean construction, load, productivity, project planning and control, reliability, throughput, variability.



Ballard, G. 1999. Improving Work Flow Reliability, 7th Annual Conference of the International Group for Lean Construction , 275-286.

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