What is "PERT" estimation?

PERT stands for Program Evaluation and Review Technique. It's a tool often used in project management to estimate how much time a task might take. It's handy when the job is complex and it's hard to make an exact estimate.

The idea of PERT is that instead of making one estimate, you make three:

1. Optimistic Estimate (O): This is the fastest time the task can be completed if everything goes perfectly.
2. Pessimistic Estimate (P): This is the slowest time in which the task could be completed if everything goes wrong.
3. Most Likely Estimate (M): This is the most probable time in which the task will be completed, considering the potential problems that might occur.

Once you have these three estimates, you combine them using a formula to get the expected time for the task. The formula is:

Expected Time = (O + 4M + P) / 6

The reason it's divided by 6 and not 3 is because the most likely estimate is assumed to be four times more likely than the other two, so it's counted four times.

Using PERT can help project managers make better estimates, especially when there's a lot of uncertainty about how long tasks will take.