Dismantling the learning curve: the role of disruptions on the planning of development projects

Any medium-run design and manufacture project requires manufacture learning to be estimated and controlled. Since the 1930's and the explication of Wright's Law, this learning has been usefully forecast using a logarithmic function. This ‘rule of thumb’ meets most practical requirements and the task of planners depends on their ability to estimate the ‘learning curve index’ from historical data. However, when projects are disrupted by clients changing their requirements by making additions or modifications, the process of estimating the impact of these changes becomes particularly difficult. The ‘rule of thumb’ has to be dismantled to account for wasted learning, the difference between corporate learning and personal learning, attributes of developmental work, retrofitting, new learning, and so on. This paper discusses the elements of disruption to learning in order that better estimates can be made of the impact of disruption. The conceptualization of learning which is presented is based upon detailed analysis for a contractor of one of the major projects for the Channel Tunnel, carried out to help compute delay and disruption for a litigation.