Predicting consequential effects of construction project changes

Changes occurring during the construction phase of a capital project are inevitable. Change effects, especially change consequential effects, have adverse impacts on project performance and profitability. This research develops a modelling methodology to improve the process of change-order pricing, particularly in identifying potential consequential or ripple effects that occur during construction. The principal focus is on the propagation concept in change prediction. Identification and assessment of likely change impacts support project management in mitigation effects. The methodology builds upon network precedence scheduling by attaching a causal diagram to each project activity. The change pricing model measures cost and durations of change effects. To support this model, a Standard Template Diagram (STD) systematizes the information required for estimating duration of each work discipline. In addition, change cause-effect pairwise relationships and a knowledge-based system relating to planning intents and activities' attribute database are identified. A prototype computer model and example illustrate both the methodology inferencing mechanism and change propagation process. The example starts with several required construction changes. The model then determines a number of adverse effects associated with several project activities. Management response actions, such as activity acceleration, are proposed by the model. Project plans can be adjusted to manage changes more effectively and mitigate "ripple effects. " Predictions of final cost and schedule include all direct, indirect and consequential effects of the imposed changes. The example and prototype computer implementation demonstrate that this enhancement of a typical precedence scheduling allows, for the first time, a systematic prediction of the consequences of construction changes. Researchers should benefit from further development of the change propagation concept, as well as the standard template diagram concept.