Forecasting expenditure on capital projects

Area of Science:

• Project Management
• Construction Economics
• Operations Research

Background:

• S-curves are essential tools for project planning, forecasting, and control of cost, time, and resources.
• Existing S-curve models require validation and comparison for practical application in health building projects.

Purpose of the Study:

• To compare the predictive accuracy and ease of use of two S-curve models: the Department of Health and Social Security (DHSS) model and the Bradford University (Keller-Singh) model.
• To validate these models using expenditure data from 21 U.K. health building projects.

Main Methods:

• Utilized the method of least squares to estimate model parameters.
• Categorized model parameters based on total project cost.
• Validated S-curve models against actual project expenditure data.

Main Results:

• Both the DHSS and Keller-Singh S-curve models exhibited comparable accuracy in fitting actual expenditure data.
• The DHSS model offers significant advantages in terms of simplicity of form and ease of use.
• The Keller-Singh model, despite slightly greater mathematical complexity, provides readily interpretable parameters.

Conclusions:

• Both the DHSS and Keller-Singh S-curve models are suitable for effective project cost planning and control.
• Clients and contractors can utilize either model, or both, for enhanced project management.
• The choice between models may depend on the desired balance between simplicity and parameter interpretability.