Collective Effort Estimation

USE CASE SCENARIOS:

Project manager need to decide about resource allocation, cost and duration of a project. This is heavily based upon estimated costs for the whole project and for all its activities.
Re-estimation often needs to be done in the course of development in order to accommodate changes.
Cost and schedule overruns can be caused by wrong estimates. These overruns can cause customers to cancel projects.
Deviation between actual and predicted estimation might cause more frequent re-planning of development processes.
Expert estimation is frequently used in practice. The quality of the results depends on the experience of the experts and the degree of novelty of the project.

BENEFITS:

Inclusion of multiple experts and combining their estimates makes the result more reliable.
Estimation by multiple experts gives a better indication of the uncertainty (the more variation, the more uncertain the estimate).
Interval estimation done by each expert also serves as an indicator of uncertainty.
More reliable effort estimates contributes to better project management, which is known as one of the key factors of project success.