Best Practice 8: Conducting a Schedule Risk Analysis

Key Questions

  1. Was an SRA performed to determine the confidence level in achieving the program schedule and other key dates?

    1. Was the schedule checked to ensure that it meets best practices before the simulation was conducted?

    2. Are there data fields within the schedule for risk analysis such as optimistic, most likely, and pessimistic durations?

    3. Were uncertainties in activity durations statistically correlated to one another?

    4. How much schedule contingency was selected and what is the probability of meeting the completion date?

    5. Did the SRA identify activities during the simulation that most often ended up on the critical path, so that near-critical path activities can be closely monitored?

  2. Was a risk register used as an input to schedule development?

    1. Was the risk register used in identifying the risk factors potentially driving the schedule before the SRA was conducted?

    2. Once the SRA was conducted, were risks prioritized by probability and magnitude of effect?

  3. Are the SRA data, assumptions, and methodology available and documented?

  4. Are the probabilities and impact ranges reasonable and based on information gathered from knowledgeable sources? Is there evidence of bias in the risk data?

  5. How is the use of schedule contingency controlled and authorized?

  6. Is an SRA performed periodically to reflect actual progress and changes in risks?

Key Documentation

  1. A risk register with prioritized risks.

  2. SRA documentation that includes assumptions, methodology, data, data normalization techniques, and findings.

  3. A listing of people interviewed or included in risk interviews along with their organizations, positions, and expertise.

  4. The schedule risk analysis file.

Likely Effects If Criteria Are Not Fully Met

  1. If a schedule risk analysis is not conducted, the following cannot be determined:

    1. the likelihood of the program’s completion date,

    2. how much schedule risk contingency is needed to provide an acceptable level of certainty for completion by a specific date,

    3. risks most likely to delay the program,

    4. the paths or activities that are most likely to delay the program.

  2. Because activity durations are uncertain, the identity of the true critical path is unknown unless a schedule risk analysis has been performed. An SRA can identify the paths that are most likely to become critical as the program progresses so that risk mitigation can lessen the effect of any delays.

  3. Unless a statistical simulation is run, calculating the completion date from schedule logic and the most likely duration distributions will tend to underestimate the program’s overall critical path duration.

  4. If the schedule risk analysis is to be valid, the program’s schedule must reflect reliable logic and clearly identify the critical path. If the schedule does not follow best practices, confidence in the SRA results will be lacking.

  5. If the program does not have sufficient schedule reserve, then risk mitigation actions and schedule issues from unforeseen events may not be managed without a schedule delay.

  6. If the task durations are not correlated to one another, the uncertainty on the critical path duration may be underestimated.