I have a resource with 50% availability for a project. I have set the Units in MS Project for 50% for him. He has a number of tasks assigned to him that can be done in parallel. How do I configure this on his schedule?

2 Answers 2


I work on lots of projects where I have a number of tasks that can be done in roughly any order, but need to be completed by a milestone. I have yet to find an ideal way to show them in a plan. Often the most efficient order changes depending on external factors. Rarely is it efficient to work in parallel on multiple tasks. I do switch tasks when the current task can't be worked on while waiting for actions by someone else.

There are two approaches to record these in the plan:

  • Just assign them in sequence, and allow him to work on them in order. Consider setting the due date to a milestone date. This will likely reduce multi-tasking an may improve performance. If some of the tasks contain long wait times, consider listing them at the beginning.

  • Add them with a percentage effort so that they run in parallel.

I don't consider either optimal, but prefer the first. You do have to live with tasks completed out of order. This may cause tasks to reorder.


Consider whether you really have to schedule each task on the plan with a definite start and end time, with tasks running in parallel and the resource assigned in a way that reflects reality. I have found that is rarely the case but if it is then you need to spend time assigning the resource to the task with appropriate percentage levels of allocation, and prioritisation of tasks together with constraints. However it is a lot of work and quickly becomes out of date when reality diverges from the plan, requiring endless maintenance of the schedule. That’s a lot of detailed work and it is normally difficult to work out what you, the PM, is getting out of that.

It is more likely that you have a bunch of tasks, that can be done in any order that works on a practical level, and you don’t care when they are done as long as they all complete on a planned date?

If that is the case then consider this procedure:

  1. Optional: Place all the tasks within a summary task for convenience

  2. Optional: Ensure the tasks are prioritised higher than normal (so that if the resource is allocated to some other task these are still done first)

  3. Let MS-Project place them in time where it likes (since it doesn’t matter to you or the resource) without using any constraints to force them into some kind of arbitrary order. Importantly the overall end date will still be the same since it is a function of the individual task durations.

  4. When the resource starts a task then mark the start date on the MS-Project task to match and begin tracking Actual Work from that date, for each task worked (whether they were “planned” to be worked on at that time or not). As work is done on any task, it doesn’t matter which, track the time spent in each task’s Actual Work. Then finally regularly Update the Project to set all (selected) uncompleted tasks after today’s date. This means that any unworked time for any task is moved to the right of today’s date (which is reality) and leaves any completed portions of tasks on the left (which is also reality)- This allows MS-P to re-plan and re-schedule all the remaining work and therefore tells you if you cannot achieve the end date.

This technique will ensure that the plan tracks reality and additionally allows MS-Project to work out whether you can still hit the overall end date for all of the tasks together.

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