Join Bonnie Biafore for an in-depth discussion in this video Balancing resource assignment variables, part of Project Management Foundations: Schedules.
When you assign resources to tasks, issues like heavy work loads and late finish dates really start come into focus. Fortunately, Resource Assignments are made up of three variables. Duration, work, and rResource availability. You can juggle these to meet schedule objectives or resolve scheduling issues. Duration is the length of a task from its start to its finish. Work, also called effort, represents the persons hours it takes to complete the task.
Resource availability is the amount of time someone has available to work on a task. Relationship between these three variables can be expressed as an equation. Duration is equal to Work, divided by Resource Availability. Like any equation, you can change any two of the three variables, but not all three. To see how this equation works, consider a task that you estimate will take someone four hours to complete. In this case, the work is four hours.
If the person assigned is available full-time, then four hours later the task should be done. So the duration is also four hours. The amount of work for a task usually stays the same. So playing with resource assignments mostly boils down to two situations. If you know how much someone is available, assign them with that resource availability. Then the task duration is based on the work hours and availability. If you know how long you want the task to take, change the duration.
The resulting resource availability is what's needed to finish the work in that duration. Not all tasks can be shortened by adding resources. In our sample project, adding more people to the task of driving to the live training site won't shorten it's duration. The care can go only so fast and let's hope it has only one driver. Let's look at an example where resource availability changes. Say the person can only work on the task half of their time, because they have another assignment. You'd expect the task to take twice as long.
The duration increases to eight hours. On the other hand, if you add another person to help, then the task will take half as long. In this case the duration decreases from four hours, to two hours. Now lets look at an example where the duration changes. Say you have a task assigned to one person that's scheduled to run for two days. But you need it to finish in one, to keep the project on time. The duration needs to be cut in half, so you need two people working on the task.
Occasionally the amount of work changes. The most common example of this is meetings. You schedule a one-hour meeting, the duration is one hour. The amount of work increases by an hour for each person who's invited to the meeting. If six people attend, the duration is still an hour, but the work is six hours. When you first assign people to tasks, you find out how long tasks should take. But you don't have accept that first answer. You can adjust assignments to reflect how much time people are available, to meet deadlines, or to get a project schedule back on track.
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- Identifying the work that needs to be done
- Adding milestones
- Delaying or overlapping tasks with lag and lead time
- Assigning resources
- Balancing workloads
- Adding buffers and baselines to the schedule
- Uncovering and correcting out schedule problems<br><br>
- The PMI Registered Education Provider logo is a registered mark of the Project Management Institute, Inc.