SAB6#59_Types_Estimations

SAB6#59_Types_Estimations

1. Activities defined and sequenced

2. Resources are identified (type and quantity)

3. Resources calendars

4. OPAs (Past project calendars, scheduling methodology, lessons learned)

5. EEFs (estimating software / productivity metrics)

6. Risks / Assumptions / Constraints should be reflected in estimations

7. One-Point Estimating (button up)

   • Submit ONE estimate per activity
   • It can lead people into padding their estimates
   • It hides important information (risks uncertainties)
   • Based on Expert Judgment or Historical Data
   • Done by the responsible of the activity

8. Analogous Estimating (top down)

   • Time and Cost
   • Based on Expert Judgment or Historical Data
   • Project of task level
   • Compare data with previous projects (similar tasks)

9. Parametric estimating

   • Based on historical records: Previous projects / Industry requirements, standards, metrics
   • 1 Regression analysis: Compares two variables to see if they are related
   • 2 Learning curve: Time will be less as efficiency improves (due to repetition)

10. Three point estimating

    • Estimations given are: Optimistic (O), Pessimistic (P) and Most Likely (M)
    • Triangular distribution (simple average) = (P+O+M) / 3
      • 3 scenarios are equal
    • Beta distribution (weighted average) = (P + 4M + O) / 6
      • Oriented to Most Likely scenario
      • Takes into consideration the benefits of risk management
    • Activity standard deviation = (P - O) / 6