The purpose of this paper is to investigate and determine the time and cost performance of progressive design-build (PDB) projects compared with that of design-build (DB) projects. The objective is to provide empirical evidence on the performance of PDB delivery method.
A quantitative research approach was used by analyzing time and cost data collected on 75 PDB and 92 DB projects from the database of Design-Build Institute of America. One-way analysis of variance was used to determine statistical difference in time and cost performance between PDB and DB.
PDB projects have a comparatively better time performance than cost performance. When compared with DB projects, there was a statistically significant difference in time overrun with PDB performing better than DB (0.41 vs 8.0%). Additionally, about 80% of PDB projects had shorter or as scheduled duration compared to 74% for DB. There was no statistically significant difference of cost performance between PDB and DB.
The main limitation is the sample size of 72 PDB projects. It is recommended that further research should be conducted using a larger sample size to confirm the findings of this study.
PDB will be more beneficial for projects with sensitive deadlines. For an owner deciding between PDB and DB, the advantage of using PDB is in its time performance, which may lead to the project being completed on or ahead of time. As such, PDB can serve as another “tool in the toolbox” for owners to help in reducing construction delays.
This paper is the first attempt to provide an empirical evidence of the cost and time performance of PDB based on analyzing multiple projects. Owners will be better informed when selecting PDB for their projects.
Adamtey, S. (2021), "Cost and time performance analysis of progressive design-build projects", Journal of Engineering, Design and Technology, Vol. 19 No. 3, pp. 686-697. https://doi.org/10.1108/JEDT-05-2020-0164
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