How to: Use Resource Assignment Percentages

This post discusses how to assign percentages to resource assignments.  Or in English, how to set how much each resource will work on a task.  By default, people in Microsoft Project are set to work 100% of their time on tasks.  But we know that’s not always practical.  People multitask their work, and may work on four tasks at once.  This post discuses how to multitask in MS Project.

Follow these steps to set assignment units in MS Project:

  1. Create a new task in MS Project
  2. Right-click before the “Start” column an choose Insert Column
  3. Insert the Work Column
  4. You should now have the Duration and Work columns next to each other
  5. Enter 16 hours into both Duration and Work
  6. Enter your Name into the Resource column

At this point, you should have a single 16-hour task that is assigned to you.  By default, it is assumed that you will work 100% of your time on this task.  But as we stated earlier, we wish to work on multiple tasks, spreading our time across them.  The steps below will do that.

  1. Right-click on your task
  2. Choose Task Information
  3. The Task Information dialog is displayed
  4. Click the Resources tab
  5. You should see your name and 100% at the right
  6. Enter 50% into the Units column and press OK
  7. Notice that the text [50%] has been added next to your name in the resource column
  8. Also notice that the duration column changed to 32 hours
  9. The finish date has also been extended to accommodate the extra time

 These steps demonstrate that the Duration column is affected by the assignment units.  Duration = Work * Units.  In other words, if you are only working half the time on a task, it will take you twice as long.  The following steps show what happens when another resource is added to the task.

  1. Right-click on your task and choose Task Information again
  2. Click the Resources tab
  3. Add another resource under your name
  4. Set the units for this new resource to 50% also
  5. Click OK
  6. Notice that the Duration went back to 16 hours because you have help
  7. Notice that the Finish date also went back to two days

We just learned that adding a new resource to a task can help it get done quicker.  Each person is working only half their time, but there are two of you, so the task is finished sooner.  You can use this technique to spread yourself around to many tasks.  But beware, this can become a little difficult to manage.