Run a Risk Analysis

Run a Risk Analysis Video

Run a risk analysis on a project to determine the likelihood of achieving your project's cost and schedule objectives. Choose a preset analysis option based on the level of detail and time it takes to calculate the analysis results. You can also customize each analysis option before starting the process. Up to 30,000 risks are supported for analysis.

Note: If any updates are made to activities, run the scheduler before running a risk analysis to ensure activity driven data is up to date.

To run a risk analysis:

  1. In the object selector, select Project, select View Projects List, and then select a project name.
  2. From the Main Menu, select Risk, and then select Risk Analysis.
  3. Select Run Risk Analysis.
  4. In the Run Risk Analysis dialog box, click and drag the slider to choose an analysis type:
    • Fast Analysis: Fewer results are calculated, but the process takes less time to complete.
    • Normal Analysis: A moderate amount of results are calculated. This is the default setting.
    • Comprehensive Analysis: The maximum amount of results are calculated. This option will increase the risk analysis time.
  5. To customize the analysis settings, select Advanced Options.

    Note: When any advanced options are modified, the slider displays Custom. Select Reset Default Options to return the slider and all options to Normal Analysis.

    • Iterations / Maximum Iterations: Enter the maximum number of iterations to be run for each risk analysis scenario.

      Note: When Use Convergence is selected, this field is labeled Maximum Iterations and the risk analysis runs until the specified convergence criteria are met, or until the analysis reaches the specified maximum number of iterations. For more information, see Understanding Convergence. You can view the Risk Analysis Log to see iteration details.

    • Select Analysis Results: Select the data that is calculated and included in the risk analysis results. Selecting all activities will increase the risk analysis time.
      • Project Only: Project cost, duration, start, and finish results are calculated. No activity results are calculated.
      • Project, Milestone and Level of Effort Activities: Project results are calculated. Only milestone and level of effort activity results are calculated.
      • Project and All Activities: Project results and all activity duration, start, and finish results are calculated.

        Note: To produce risk iteration analysis results, you must select Project and All Activities.

    • Risk Removal Impact Analysis: Select this option to run a risk removal impact analysis for the selected response contexts. A risk removal impact analysis measures and ranks the potential impact of each risk on the cost and completion date of the entire project. The analysis also measures and ranks the potential impact of activity uncertainty on the completion date of the project.
    • Proposed Risks: Choose to include risks with a status of Proposed during the risk analysis.
    • Response Context: Select the context that will be run during the risk analysis.

      Random Number Generator Seed: Set a seed for the random number generator. Random numbers are used in the risk analysis to sample the distributions on values such as activity duration, risk probability, and risk schedule impact.

      The random number generator used by the application requires an initial seed to set the starting point for generating a series of random numbers. The seed controls whether the generator produces a new set of random numbers or repeats a specific sequence of random numbers.

      If the same number is always used to seed the random number generator, then the same random numbers will be created each time. Setting the same number for the seed produces the same iteration analysis results providing the model has not been changed in a way that causes the distributions to be sampled with different random numbers, such as adding a new distribution to an activity or changing the number of risks.

      Using the same seed enables one or more distributions to be changed within the model. When re-running the risk analysis, the effect that these changes have on the results can be observed. Because it is using the same seed, any observed change in the result is due to changes in the model's existing distributions and not a result of the randomness of the sampling.

      Using the same seed can also be useful when presenting the results of a risk analysis when combined with a demonstration of how those results are created. This will ensure the results match in the documented presentation notes and the real-time risk analysis.

      If a random seed is used, the application uses the current clock time to seed the random number generator each time an analysis is run.

      If a risk analysis gives significant variations in the results when the seed is changed, then the number of iterations being run is probably not sufficient. The convergence risk analysis can be used to help ensure that the risk analysis performs enough iterations.

    • Seed: Enter the number to be used to set the starting point for the random number generator.

      Note: Random number generator options are not available if you choose to use convergence during the risk analysis.

    • Use Convergence: Select this option to automatically determine when enough iterations have been run on a model.

      As the risk analysis is performed, the results begin to converge to such an extent that there is no point running the analysis any further as the result is only changing by a small percentage. At this point, the analysis is said to have converged and is automatically stopped. If this option is selected, the analysis is run until the convergence criteria that have been set are met or the analysis reaches the maximum number of iterations.

    • Schedule Cost: When this option is selected, the activity costs can vary for each iteration. This will increase the risk analysis time. If not selected, the activity costs will remain fixed for each iteration. The toggle is off by default.
    • Convergence Threshold: The maximum percentage deviation at which analysis results are considered converged.
    • Convergence Iteration Frequency: The number of iterations that are run before the analysis results are retested for convergence.

      Note: For more information on convergence options, see Understanding Convergence.

    • Optimistic Percentile: Enter the value (0% to 100%) to be used to calculate optimistic percentiles.
    • Pessimistic Percentile: Enter the value (0% to 100%) to be used to calculate pessimistic percentiles.
  6. Select Run Risk Analysis to start the analysis process.

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