Using historical data for forecasting S-curves at construction industry

Cash flow forecasting and control are essential to the survival of any contractor. The time available for a detailed pre-tender cash flow forecast is often limited. Therefore, contractors require simpler and quicker techniques which would enable them to forecast cash flow with reasonable accuracy. The paper is based on classifying projects into groups and producing a standard curve for each group simply by fitting one curve into the historical data A sample of data from 7 projects was collected which all of them were harbor construction project in Iran. S-curves were fitted into each using the logit transformation technique. Errors incurred when fitting these curves were measured and compared with those associates in fitting individual projects. Results showed that the difference between these errors was not significant. The results of the model developed in this paper were compared with previous models and evaluated. It is concluded that the model produced more accurate results than existing value and cost models