Managing Uncertainties

If you have accurate historical statistical data that is analogous to a particular element in your project, we recommend that you use this data to model uncertainty in your project as opposed to risk events. Be aware of double-counting risk and uncertainty as most of the uncertainty in a project is due to the probability of risk events occurring.

To define uncertainties:

1. Define a 3-point estimate for any of task parameters: cost, income, duration, and start time. 3-point estimates for work will be calculated automatically based on uncertainty in duration. You may also define 3-point estimates for the lag.
2. You can define a Most Likely duration or fixed cost. By default, Most Likely duration or fixed cost equals Base duration and Fixed Cost. However, you can define separate Most Likely values. This can be used if you believe that the Base values from original project schedule is not realistic, but you want to maintain the original Base values. Most Likely values are used only with Triangular and BetaPert distributions.
3. After you define 3-point estimates, a statistical distribution will be assigned. You may change the default statistical distribution for the duration, cost, income, and start time parameters in Distributions tab of Task Information dialog box.

The meaning of low, base, and high data depends on the statistical distribution defined in the Distributions tab of the Task Information dialog box.

See also

Risks in RiskyProject
Risk Register