From the course: Project Management Foundations: Schedules

Include schedule contingency time - Microsoft Project Tutorial

From the course: Project Management Foundations: Schedules

Include schedule contingency time

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- [Instructor] Schedule contingency acts as a safety margin that helps you deliver your project on time. Work estimates are, by definition, uncertain. They're based on assumptions about work, resource availability, people's experience, productivity, and so on. If your assumptions are off, activity durations might lengthen or shorten. Risks that occur can also affect your project's duration and schedule. For example, a construction project could be delayed by a long stretch of bad weather. Don't build contingency time into individual work package activities. That makes contingency hard to manage and lengthens the schedule unnecessarily. Instead, add separate contingency activities to your schedule so you can monitor and manage them. Add contingency activities for specific reasons. For example, to get up to speed on new technology or bring on new people. These contingency activities clearly communicate your reasoning to management and assure them that you aren't simply padding the schedule. Suppose management wants a 90% probability of finishing on or ahead of schedule. With a normal distribution like this one, in statistical analysis, 90% probability of success is halfway between the most likely and worst case duration. If the most likely estimate of duration is 30 weeks and the pessimistic estimate is 36 weeks, the 90% probability of being on time is 33 weeks. For small projects, you can guesstimate the amount of contingency based on project duration, risk, and so on. As you gain experience, you can fine tune contingency to fit your projects and teams. Start by adding a contingency activity to the end of each sequence of activities. That way, all the activities in the sequence share one buffer. If an activity needs more time, you allocate it to that activity. In the sample project, one of the sequences is writing the manuscript. This sequence has five activities with a total duration of 45 days. Let's add a buffer of, say, five days, approximately 10% of the duration at the end of the sequence. Next, add additional contingency to the end of each phase or major section. These buffers help address the schedule risk that arises when multiple paths merge in a schedule. Finally, add one more buffer at the end of the project. In the example, there's a five-day buffer at the end of the training guide production phase, a buffer when the guide is published, and another five-day buffer at the end of the website work. In addition, there's an eight-day buffer at the end of the project right before the project closure activities. By adding contingency in this way, you don't have to take action at the first sign of a problem. You can remain focused on keeping the overall project running smoothly. If an activity experiences a delay, you give it some of the buffer at the end of its sequence. If a third of the buffer gets used up, start watching activities more closely, but you still don't have to take any action. When half the buffer gets used up, put plans in place for correcting course if the delays continue. Finally, if 2/3 of the buffer gets eaten up, implement the plans you made. If an activity sequence extends beyond its buffer, you can start using the phase buffers in the same way to protect the project finish date. For example, if a delayed sequence consumes more than a third of a phase buffer, you would evaluate additional options to get the problem under control. By adding contingency to your schedule, your project is more likely to finish on time.

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