Fewer Design Errors in CMAR?

Owners did not believe there were far fewer design errors in CMAR, while the other parties felt there were

When asked if there were far fewer design errors in CMAR compared with DBB, Owners disagreed while the other parties agreed.

The issue of design errors in CMAR has not been researched to my knowledge. One would expect there are fewer design errors in CMAR because there has been a design review by the CM and the Subs. Even if the Subs were not part of the preconstruction team, the qualifications aspect of CMAR contracting gives them an incentive to bring errors to the Owner’s attention early in the process and to not make a fuss about minor design problems.

So, expecting to find far errors we asked, “Relative to DBB, there are far fewer design errors problems in CMR. Score 1-5, where 1 means strongly agree and 5 means strongly disagree.”


The question seem to ask about the number of design errors rather than their total impact, but we can assume that the respondents took importance of the changes into consideration. The overall average, 2.73, indicates slight agreement. There is a clear trend that Owners disagree with A/Es, CMs, and Subs. Owners at 3.5 slightly disagree, while the others at 2.5 slightly agree and the difference between the Owner and the A/Es is significant. We found no significant difference for CMAR experience.  

I don’t have a good explanation for why Owners do not see far fewer design errors in CMAR, while the others do - the difference between the Owner and the A/Es is significant. Owners typically pay for the error with cash, while the A/E pays with reputation and manhours for redesign. The CM and Subs may get paid their cash costs, but generally have disruption that is not compensated. A positive effect of teamwork would be that the hassle and embarrassment of design errors is reduced and their rectification is done more quickly and at less cost than DBB, but the number of errors is about the same. (In another section we discuss CM and Subs ignoring minor changes.)

One explanation may be pride-related. If CMs and Subs are involved in the design, they do not feel the errors are a common as if they are not involved in the design – just a guess. The feeling of A/Es is not accounted for by this – they have pride, of course, but it would be the same on DBB and CMAR.