Public sector design-build: A model for project selection

The use of design-build project procurement is rapidly increasing in the public sector. Documented design-build success and recent changes in federal procurement law are indicators of continued large-scale growth. The rapid growth, combined with a lack of experience among many public agencies, spawns a variety of issues which must be addressed. One issue is proper project selection. As new agencies experiment with design-build, appropriate project selection is a primary consideration affecting successful delivery. To date, there is no systematic or formalized method for selecting projects which are appropriate for design-build. This research presents a model which can be used in the earliest stages of project selection to enhance the chances of design-build project success. The hypothesis proven true by this research is that there are public sector projects which are appropriate for design-build and success is predictable. Key project characteristics which are appropriate for design-build projects are identified and a statistically based model is presented. Using multi-attribute analysis, retrospective case study data collection methods, and multiple regression modeling, this research produces a model which predicts the success of the design-build process on future projects. Design-build project success is defined in this study by five measures: (1) budget variance, (2) schedule variance, (3) conformance to expectations, (4) administrative burden, and (5) overall user satisfaction. These five measures of success are the dependent variables for the multiple regression models. The independent variables are found in the inherent characteristics of the project, owner, market, and relationship between the owner and design-builder. Through retrospective case study analysis, five models are developed to predict design-build success. These models are validated by statistical means, as well as additional case studies. Other significant findings in this research include the categorization of public sector design-build variations and their impact on project success, an enriched understanding of the public sector design-build contracting method, and an enhanced knowledge of predictive tools in construction. This research is the beginning of an improved understanding of procurement and predictive tools for the construction industry.