In Agile, PERT stands for Program Evaluation and Review Technique. It's a method used specifically in Agile estimation to get a more detailed and realistic view of how much effort a task might require.
Understanding PERT in Agile Estimation
While Agile often favors simpler estimation techniques, PERT is sometimes incorporated, particularly for tasks with higher uncertainty. The core idea is to move beyond a single-point estimate and consider a range of possibilities.
Based on the provided reference, here's how PERT is applied in Agile estimation:
- It utilizes the Program Evaluation and Review Technique.
- For each task, you incorporate three different estimates:
- Optimistic (O): The best-case scenario estimate, assuming everything goes perfectly.
- Pessimistic (P): The worst-case scenario estimate, accounting for potential issues or delays.
- Most Likely (M): The estimate based on normal conditions, what you'd typically expect.
Calculating the Expected Duration
The reference states that you average these estimates to calculate the expected duration or effort for the task. A common formula used for this average in traditional PERT (and often adapted for Agile) is:
Expected Duration = (O + 4*M + P) / 6
This formula gives more weight to the "Most Likely" estimate.
Why Use PERT in Agile?
Using the three estimates and the calculated average provides a more comprehensive and nuanced view of the potential effort required. Instead of just one number, you understand the potential range (from optimistic to pessimistic) and a weighted average that balances these extremes. This can be helpful for planning and managing expectations, especially for complex or uncertain backlog items.
In summary: While Agile promotes flexibility, PERT offers a structured way to think about potential variability when estimating tasks by considering best-case, worst-case, and typical scenarios.
