Working with overallocations in Microsoft Project 2002

by Brian Kennemer | Oct 21, 2002 7:00:00 AM

Tags: Brian Kennemer

Takeaway: Every project has a finite amount of time and resources that can be devoted to completing tasks. Overallocation, when a project calls for more time than a team member has, can present serious problems. Learn how to work around this dilemma.

In a perfect world, we would always have enough people and ample time and money for every project. Most days, this is not the case, and we are left to deal with the scarcity of resources by trying to squeeze everything in where we can.

In these situations, errors often occur. I’ll show you how to remedy the problem of overallocated resources when you’re working with Microsoft Project 2002.

What is overallocation?
A resource is considered overallocated if more time is scheduled for it than it has available. In project management terms, a resource is overallocated if at any point the resource is allocated to a level greater than its maximum units value.

In practical terms, that means that if the maximum units value for a resource is 100 percent, and that resource is assigned to work more than one minute of work in any one-minute period of time, it is overallocated. This is important because it means, for example, that a resource assigned to work on two, one-hour tasks during a day can be marked as overallocated if the tasks overlap by even one minute.

While overallocations can seem very complex, their solutions are fairly straightforward.

1. The work needs to be spread out over a longer period of time. (A resource is assigned to work on a single task for 15 hours in one day.)
2. Some or all of the work needs to be assigned to another resource. (A resource is assigned to work on two, six-hour tasks in a single day.)
3. One or more tasks need to be rescheduled to happen at different times.

Figure A shows part of a project plan with several overallocations. In this example, Dell and Neil are both assigned to work on the Review Specification Updates task, at different times. Neil is scheduled to work at 100 percent allocation for the first three days of the task, and Dell does the same amount of work for the last three.


Dell is also scheduled to work on the Review Development Plan task during the same time period as his work on the first task. There are a couple of solutions to this problem.

1. Get someone else to do the work on the Review Development Plan task. This would free Dell up for the Specification task.
2. Have Dell and Neil switch order on the Review Specification task so that Dell does his review before Neil. This would resolve the conflict between the two tasks (see Figure B).

In Figure B, you can see the results of switching the order in which Neil and Dell work on the Review Specification Updates task. I entered eight hours for the Wednesday, Thursday, and Friday cells of the Review Specification task for Dell and then removed the eights from the Monday, Tuesday, and Wednesday cells.

I then did the opposite for Neil. This flexibility of entry and control of the distribution of work is what makes the Resource Usage view a great tool for resolving overallocations. This resolves Dell’s overallocation.

There are still problems with Neil’s allocation. We could try to delay Neil’s contribution to the Specification Review task until after the other tasks, or we could try to have someone else do the review for him. We could also try to get someone else to do the Develop Test Plan task or delay it until after the Develop Marketing Plan task.

Because of the role that the overallocation on the Marketing Plan task will play in how we resolve the conflict between the Specification and Test plan tasks, we should work on the overallocation on the Develop Marketing Plan task first. Again, we have to ask ourselves whether anyone else can do this task or whether there’s any way for this task to happen later or even earlier.

For this example, we’ll assign it to someone else. The best way to do this is to select the task in the Gantt chart—which is the default view in Project—and then click the Assign Resources toolbar button to bring up the Assign Resources dialog box shown in Figure C.


Click the Replace button, select the new resource from the list, and enter 100 for the Units, as shown in Figure D. This will assure that the new assignment is not at the 125 percent figure that the previous one was—we’ll solve that overallocation in the process, too.


Now that we have that out of the way, we can deal with Neil’s conflict on the Develop Test Plan task and the Review Specification Updates review task. For our example, we’ll assume that Neil is the only resource that can do either of these tasks; we’ll move his assignment on the Specification task to after the Test plan task is complete. Figure E shows the results of this move.


We have replaced the hours in the Monday, Tuesday, and Wednesday fields for the Specification task for Neil (visible in Figure B) with zeros. We then put the hours in the Thursday, Friday, and Monday fields to add a split in the task. This means that no work will be done on that task during those three days. This allows Neil time to do the Test Plan task.

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