The MacLeamy Curve, named after Patrick MacLeamy, a former CEO of the international planning and consulting firm HOK, illustrates the relationship between the cost of design changes and the progress of a construction project. It shows that the cost of design changes varies over the course of a project.
In the early stages, such as the concept and design phases, design changes are relatively inexpensive. However, as the project progresses and construction begins, the cost of changes increases significantly. Later stages of construction can actually become very expensive and time-consuming, as changes affect work already done and require additional resources.
The MacLeamy Curve highlights the importance of early decisions and careful planning to minimize costly changes during construction. A BIM-project shows that the additional effort is in performance phases 2 and 3, before design freeze and before construction submission. This shows that early identification of problems or changes in the construction process can help minimize the overall cost of the project.
