My organization has created a yearly enterprise operational schedule for our IT workers. Each worker has an engagement registered that sets their Max hours for allocation to the schedule. We assign the resources to tasks in a fixed duration schedule. At the start of the new month, we reconcile planned hours to actual hours and we adjust the duration so that the planned finish date is aligned with the baseline finish date. The problem we’re experiencing is unused hours are pushed to the future months causing the resources to be over-allocated for future months. Is there a better way to manage the application of those unused hours? Should we use fixed work instead of Fixed duration?
Jeff. The last company I worked for had a very similar operational work approach. We organized it based on % availability, or Fixed Units. For example if Bob (100%) has 15% overhead time for operational work, Bob would be allocated to the operational schedule as Fixed Units at 15%. That way, he is never allocated more than 15% per week/day/month. Unfortunately, MS Project doesn’t have a good approach to a level of effort task providing a “use it or loose it” option. Meaning when I allocate you 15% across each month, if you only use 10% in May, the other 5% does NOT roll forward and muck up the remaining months allocations. So with MS Project, and Fixed Units, durations and end dates will move earlier or past your scheduled end date, but as you’ve noted, that can easily be adjusted on a monthly bases to move individual resource allocations forward (if they applied too much time) or backward (if they applied less than expected time).
Note that with Fixed Work or Fixed Duration, unused work will roll forward and the Units allocation will be changed without your knowledge. As a result, their individual allocation will start to change as the year goes by. If they used more work than planned, Bob for example, may only be allocated at 8% in December. But if Bob used less than planned, he might be 75% allocated in December. So the only way to ensure Bob stays at 15% is to set the task as Fixed Units, which then means adjusting task end dates.
As a side, MS Project has a background formula on every task that controls this. The formula is Duration = Work / Availability (which is units/day). Setting a task as Fixed Duration locks the Duration part of the formula and if anything changes, Work or Units will be adjusted (without telling you) to keep the formula in balance. Fixed Units locks the Availability part, and Fixed Work locks the Work component. Once you understand this it becomes easy to understand why MS Project adjusts one of these parameters every time you update the task or update the schedule.
Note that the other side of this operational work equation was an understanding across all PMs and the resource managers that project work can not exceed 85% (in the Bob example) across ALL of his projects. So it was up to the resource managers to say that I could have Bob at 85% for my project, knowing that he’s already allocated at 15% to operational work.
I hope that helps.