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Work Flow Variation and Labor Productivity: Case Study |
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| Authors: | Min Liu Glenn Ballard William Ibbs |
| Affiliation: | 1Assistant Professor, Dept. of Civil, Construction, and Environmental Engineering, North Carolina State Univ., 208 Mann Hall, 2501 Stinson Dr., Raleigh, NC 27695 (corresponding author). E-mail: min_liu@ncsu.edu 2Associate Adjunct Professor, Univ. of California, Berkeley, CA, and Research Director, Lean Construction Institute. E-mail: ballard@ce.berkeley.edu 3Professor of Construction Management, Dept. of Civil and Environmental Engineering, Univ. of California, Berkeley, CA 94720, and President, The Ibbs Consulting Group, Inc. E-mail: William.Ibbs@IbbsConsulting.com |
| Abstract: | Different types of flow variation and how they affect construction project performance have been studied by previous researchers. One aspect that has not been well researched is how work flow variation and labor productivity are related in construction practice. To study that issue, 134?weeks of project production data were collected and analyzed to explore this relationship. Labor productivity was found to be positively correlated with Percent Plan Complete (PPC), a measure of work flow variation. The relationship between productivity and the ratio of total task completion to planned tasks, weekly workload, weekly work output, and weekly work hours was also studied, and no significant correlation was found. The results suggest that productivity is not improved by completing as many tasks as possible regardless of the plan, nor from increasing workload, work output, or the number of work hours expended. In contrast, productivity does improve when work flow is made more predictable. These findings can help project managers focus on actual drivers of productivity. It can also help consulting companies pinpoint responsibility for productivity losses in claims. |
| Keywords: | Construction management Labor Productivity |