Best Practice 4: Establishing Durations for All Activities

Key Questions

1. Were durations determined from work to be done and realistic assumptions about available resources, productivity, normal interferences and distractions, and reliance on others?

2. For a detailed schedule, are durations short enough to be consistent with the needs of effective planning and program execution?

3. Are activities long in duration because of LOE or rolling wave planning?

4. Are LOE activity durations determined by the activities they support?

5. Did the person responsible for the activities estimate their durations?

6. Was the program duration determined by some target or mandated date?

7. Are durations based on appropriate calendars? Do any specific conditions necessitate special calendars, and are they addressed (for example, religious holidays, nonwork periods for climate, shift work, unavailability of resources)?

8. Are activity durations assigned inconsistent time units?

Key Documentation

1. How durations of work activities were estimated is documented at the appropriate level of detail. For instance, the basis of estimate includes the assumptions made to justify the durations assumed for the cost. These should be consistent with the durations at the same level of detail.

2. Documentation justifies nonstandard working calendars.

3. Documentation justifies excessively long durations, including the identification of LOE activities and how they were scheduled.

Likely Effects If Criteria Are Not Fully Met

1. If activities are too long, the schedule may not have enough detail for effective progress measurement and reporting.

2. If activities are too short, the schedule may be too detailed. This may lead to excessive work in maintaining the logic, updating the status of activities, and managing the many short-duration activities.

3. When durations are not based on the effort required to complete an activity, the resources available, resource efficiency, and other factors such as previous experience on similar activities, then there is little confidence in meeting the target deliverable date.

4. Schedules determined by imposed target completion dates rather than work and logic are often infeasible.

5. Durations estimated under optimal or “success-oriented” conditions will produce unrealistic program delivery dates and unreliable critical paths and could mask program risks.

6. Proper use of resource and task calendars usually precludes the need for soft constraints in schedules. But improperly defined task or resource calendars incorrectly represent the forecasted start, finish, and durations of planned activities. Ensuring realistic calendars provides for more accurate dates and may reveal opportunities to advance the work.

7. The default calendar in a schedule software package rarely has appropriate national holidays defined as exceptions and will not have specific blackout periods or other project-specific exceptions defined.