According to the PMBOK Guide, the Estimate Activity Durations process is the process of estimating the number of work periods needed to complete individual activities with estimated resources.
* Parametric Estimating: This is a core tool and technique used in this process. It involves using an algorithm or a statistical relationship between historical data and other variables (e.g., square footage in construction, lines of code in software development) to calculate an estimate for activity parameters, such as cost, budget, and duration.
* Accuracy: The accuracy of this method depends on the sophistication and underlying data built into the model. It is generally more accurate than analogous estimating when the data is reliable.
* Example: If the historical data shows that a painter can cover 20 square meters per hour, and the total area is 200 square meters, the parametric estimate for the duration would be 10 hours ($200 /
20 = 10$).
Comparison with other options:
* A. Critical path method (CPM): This is a technique used in the Develop Schedule process to calculate the theoretical minimum duration of the project. It uses the activity durations (which were already estimated) to find the path with the least amount of float.
* B. Rolling wave planning: This is a technique used in the Define Activities process. It is a form of iterative planning where the work to be accomplished in the near term is planned in detail, while future work is planned at a higher level.
* C. Precedence diagramming method (PDM): This is a technique used in the Sequence Activities process to create a schedule model by representing activities as nodes and showing their logical dependencies (Finish-to-Start, etc.). It does not estimate the duration of the tasks themselves.