The design of project estimating systems

Ineffective estimating practices cause major problems within the construction industry, exemplified in common failures to meet project objectives. There is much scope for improving estimating practice throughout the industry, however, estimating techniques must be considered within the context of complex organisational environments.In practice there are many factors which influence the compilation and use of estimates. The thesis presents a holistic view of the project system by linking estimates of cost, time and performance and reveals a wide range of social and organisational pressures which act to influence estimating practice.In particular this research examines the application and management of risk contingencies in the cost, time and performance objectives, and provides a model to explain the effect of dependency between these elements. The project estimating system is central to the task of project management and the research shows that, in practice, estimates must be designed for a variety of purposes, which require different methods of compilation and interpretation. Findings resulting from an original research methodology, based upon an interpretative approach, broadly shift the boundaries of existing cost estimating theory and facilitate the development of a systematic framework for the design of project estimating systems. This framework may provide the construction industry with a basis for redefining current practice.