First developed 60 years ago, the critical path method is now common practice among large contractors, and a recent survey of ENR Top 400 Contractors shows that practitioners are applying the tool and unlocking its benefits. Although CPM is not always required on every job, all 101 respondents to the 2017 survey report that they use CPM, with 97% indicating that it is a valid management tool.
More large contractors are reaping rewards from CPM, particularly in estimating and bidding. Based on past surveys conducted in 1970, 1987 and 2003, a large majority of Top 400 contractors see improved planning, scheduling and project controls with CPM. Since the 2003 survey, nine in 10 respondents have reported these benefits.
Notably, a majority of contractors now see the advantages of CPM in estimating and bidding. Among respondents, 55% observed that CPM improved estimating and bidding, up from 15% in 1970, 22% in 1987 and 37% in 2003.
Jesus de la Garza, the Vecellio professor of construction engineering and management at Virginia Tech, suggests that contractors are becoming more aware of the benefits of “mapping the level of detail from the work breakdown structure with the cost breakdown structure to readily deploy earned-value management practices during project execution.” De la Garza, who conducted the 2017 survey, notes, “Contractors are realizing that, in many instances, a more accurate and precise bid is produced by bidding the schedule of work, as opposed to merely bidding the work in a sequencing vacuum.”
Conversely, fewer contractors report disadvantages with respect to CPM. Roughly half of respondents see no major disadvantages, nearly double the rate reported in the 2003 survey. Significantly, concerns that construction personnel are not using it have dropped considerably. In 1987, 63% reported lack of use as a concern; that rate dropped to 24% in 2003 and to only 10% in the latest survey.
Andrea Rutledge, president and CEO of the Construction Management Association of America, says the advantages of using CPM schedules “far outweigh” the limitations. “The timing of estimating and bidding is vastly improved with the adoption of CPM, and CPM leads to improved project control, which affects the estimating and bidding process,” she adds.
As part of the survey, respondents were asked about the other planning techniques they use. Nearly half of large contractors reported using the pull planning method to coordinate work and track production, and more are using 4D scheduling.