Pre-Design Methodology for Establishing Scope-Budget and Scope-Duration Alignment for Capital Projects

Abstract

Pre-design Methodology for Establishing Scope-Budget and Scope-Duration Alignment for Capital Projects It is well established that projects do not meet their cost, schedule and scope objectives and often fail to deliver the benefits that were hoped for. Part of the challenge is that at the conceptual/pre-design stage, the level of scope definition is often only 1-2% and the resulting pre-design cost estimates typically have an accuracy range of -50% to +100%. Project teams may not feel confident providing this information to the designers as design-to-cost targets and overall project cost management suffers as a result. The proposed methodology was developed to assist with pre-design estimating on a new student health center at a college in the mid-Atlantic region of the United States. Development of a preliminary work breakdown structure allowed development of a cost model targeted at the major cost elements of a capital project by removing cost elements such as sitework and general conditions that have greater variability that is often concealed in cost/SF historical data used for modeling. The regression equation developed, based on five data points of comparable projects ranging in size from 20,000SF to 72,714 SF , with a zero intercept, has an R² of 0.9925, a P Value <0.0001 and a F test score of 661.63. 63. Using the model to validate the cost of the comparable projects resulted in a cost forecast range of -10.3% to + 39.4% as compared to industry standard expected cost range in the pre-design period of -50% to+100%. Using the forecast cost and Bromilow equations to forecast project duration resulted in duration forecasts within approximately +/-18% of the contracted durations. The need for vigorous cost management over the life of a project remains, but this methodology offers an approach to (1) develop design-to-cost targets and (2) for the project team to have greater confidence they have scope-budget and scope-duration matches as the project enters design.