Comparative Analysis of CM/GC vs. Design Bid Build
The summary of this comparative analysis is based on information obtained nearly ten years ago. Please understand that the comparison’s accuracy is limited due to its age, and due to conflicting opinions on which procurement method is the most cost effective throughout this particular construction process.
In January 1999, the Beaverton School District conducted a cost comparison on two recently built schools. One school was built using Design-Bid-Build while the other used CM/GC. The site using CM/GC required an additional $857,166 in site prep, otherwise the sites and designs were analogous. This unique situation allowed the District to analyze the differences between the methods. According to analysis by Brent Shafer of Todd Construction, Inc., the CM/GC project appeared to cost $666,590 more than the Design-Bid-Build project (once site-specific costs were removed). Schafer concluded that the CM/GC project was 11% more expensive. In addition, the recommendation to combine bidding with CM/GC saved the Beaverton School District over $1 million. Further information on Todd Contruction’s analysis of the CM/GC process can be accessed here (.pdf).
Oregon [3] is one of the few states that allows contractors to be selected based on qualifications, rather than lowest bid. Because of this, there is little data available to support or deny the effectiveness of CM/GC. Gerald H. Williams, Jr., Ph.D., P.E. of the R. Brown Consulting Group, analyzed the cost differences. Dr. Williams assembled a panel of 30 industry professionals to elicit advice on appropriate measures of performance, and collected raw data. He identified 215 projects that would allow him to compare CM/GC and Design-Bid-Build.
Dr. Williams concluded that CM/GC is more technically efficient (on the basis of fast tracking construction), but does not result in statistically significant cost differences. During his research, he found that owners felt better taken care of and more involved with CM/GC. The team recommended owners make decisions based on scheduling concerns rather than cost. CM/GC is useful when a project needs to be fast tracked, and there is a set deadline.
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