An Investigation of the Expanding Role of the Critical Path Method by ENR'S Top 400 Contractors

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Virginia Tech

The Critical Path Method (CPM) is a widely used tool throughout the construction industry. Since its creation, the use and application of the Critical Path Method has grown tremendously. Up to date, three studies have been performed on how Engineering News Record's (ENR) Top 400 Contractor use CPM. The first study was performed by Edward Davis in 1974 and the second was performed by Amir Tavakoli and Roger Riachi in 1990. This paper is a summary of the third survey, which took place in 2003. The results from the three studies indicate that CPM use by the Top 400 Contractors is growing and the areas of use are expanding. The number one use of CPM throughout the years is detailed planning before the start of construction. Periodic control during construction is another large area of CPM use and has been a large area of growth due to the advances in technology, which make updating a schedule during construction easier and faster than was possible with a mainframe computer in the past. Another area of CPM growth is estimating and bidding for several reasons: use in this area has jumped from 19% to 54% in the past 30 years. An area of concern lately in CPM is the use of precedence diagramming instead of arrow diagramming. Despite the debate, the responding companies found precedence diagrams easier to read, provide more flexibility, and allow for easier use of "smart" relationships (i.e. start-start).

scheduling, CPM, ENR Top 400