Good planning alone does not ensure project success. Real world circumstances like project scope changes, human errors in effort estimation, miscommunication and so on cause project plans to derail. Celoxis provides time and cost estimation so as to alert the manager well before crisis strikes. Project time estimation is calculated as a weighted average of the progress of all its tasks. Hence team members need to regularly update the status of the work assigned to them and account for their time and expenses. Read Task Health (Section 8.11) for more information on how projections are made.