- Delphi cost estimation approach tries to overcome some of the limitations of the expert judgment approach.
- Delphi estimation is carried out by a team comprising of a group of experts and a coordinator.
- In this approach, the coordinator provides each estimator with a copy of the software requirements specification (SRS) document and a form for recording his cost estimate.
- Estimators complete their individual estimates anonymously and submit to the coordinator.
- In their estimates, the estimators mention any unusual characteristic of the product which has influenced his estimation.
- The coordinator prepares and distributes the summary of the responses of all the estimators, and includes any unusual rationale noted by any of the estimators.
- Based on this summary, the estimators re-estimate. This process is iterated for several rounds.
- However, no discussion among the estimators is allowed during the entire estimation process.
- The idea behind this is that if any discussion is allowed among the estimators, then many estimators may easily get influenced by the rationale of an estimator who may be more experienced or senior.
- After the completion of several iterations of estimations, the coordinator takes the responsibility of compiling the results and preparing the final estimate.