Primavera P6 Professional has the capability to level resource allocations when they become overloaded across a number of activities. This can be a particularly valuable feature when you have a resource constrained project that includes a scarce resource whose skills cannot easily be hired in to overcome shortfalls.
This article discusses the fundamentals of resource leveling in Primavera P6 Professional to help you better prepare for resource allocation coordination efforts.
In preparation for the coordination of limited resources on a resource-constrained project, the resource manager would want to bracket the impact of resource allocations. Two extremes to consider are the project end date for a completely resource-leveled schedule and the project end date for a completely non-resource-leveled schedule.
This provides the resource manager with an understanding of the resource allocation influence on the schedule in support of resource coordination with stakeholders. The completely resource-leveled project end date would be the longest the project will take. And none of your resources would have to work overtime. The non-resource leveled schedule is the absolute shortest schedule based on your activity durations and logic.
As it is not adjusted to remove resource over-allocations the non-leveled schedule is not a realistic schedule; you do not want to commit resources based solely upon a non-leveled resource project end date. The assignment of resources should be based upon a schedule duration falling somewhere between the completely leveled and the completely non-leveled schedules. Ideally, you will want to at least resource level your schedule within the available activity float.
You may want to specify a minimum float to preserve throughout leveling and also a maximum acceptable resource over-allocation. The minimum float specification is the resource manager’s opportunity to provide some resource allocation buffer to the agreed upon completion date. The maximum percent to over-allocate resources is the resource manager’s opportunity to specify an acceptable resource overtime amount.
In Figure 1 is a demonstration project.
This contains a project deliverable Project Planning and five activities: ‘Start Project Planning Phase’ (start milestone), ‘Write Statement of Work’, ‘Write Safety plan’, ‘Acquire Permits’, and ‘End Planning Phase’ (finish milestone). All relationships are finish to start (FS). As displayed in Figure 1, the Project Manager (PM) is budgeted to work 40-hours on ‘Write Statement of Work’. The PM is also budgeted to work 24-hours or 3-days on write safety plan, Figure 2.
No resources are assigned to acquire permits.
It is important for this demonstration that the budgeted units/time be 8.0h/d (100%) for both PM activity assignments. As per Figure 3, in the resource usage profile, we see that the PM is over allocated by 8-hours on Monday, Tuesday, and Wednesday.
The Primavera P6 Professional level resources tool in the top Tools drop down menu provides options for leveling the activity resources, Figure 3. First note that you can toggle to level all resources or select resources from a list. In our demonstration we select to level all resources. Another option to note is ‘level resources within activity total float’. If you toggle ‘off’ this option and level all resources than your schedule levels completely, and your schedule end date is delayed, accordingly.
As mentioned previously, you will want to understand the extremes between completely unleveled and completely leveled. However, to find not only a realistic schedule, but one more agreeable with your sponsor stakeholder toggle on ‘level resources only within activity Total Float’. With this toggle on, your schedule will adjust according to the minimum float to preserve and maximum allowable over-allocation percent you specify.
In Figure 3 the minimum float is 0-hours and the max percent to over-allocate is 0%. When we level the schedule, Figure 3, we find that our write safety plan activity shifts right and fits perfectly in the cavity (i.e., empty or available unallocated resource time) between the end of write statement of work and the September 14th, finish milestone, Figure 4.
In this situation, the schedule finish date held, which it should because we leveled resources within available total float. The good news is that we completely leveled our resources with our planned finish date. We thus have a schedule agreeable to both the project resource manager and the project sponsor.
The resource manager, however, may want a more conservative schedule to accommodate possible delays, so we set the minimum float to preserve or buffer to 8-hours (1-day), Figure 5.
This time, when we again level the schedule, the write safety plan activity does not fit in the cavity, and the level resources tool provides no schedule leveling adjustments, Figure 6.
Two changes are made to better define and level the schedule. First, the max units/time of the PM is increased to 12h/d (150%) on September 8th, Figure 7.
This means you have one full-time project manager and another project manager working part-time. Second, the max percent to over-allocate resources is set to 50%, Figure 8.
With these two adjustments, and while maintaining the 8-hour minimum float or buffer, we level the resources. The resulting schedule is displayed in Figure 9.
The write safety plan activity shifts right to commence on Thursday, September 8th. So on September 8th and September 9th, we have two project managers working on the schedule: one working 12-hours or 4-hours overtime and one working 4-hours or halftime. On Monday we are under allocated and have one project manager working full time though the second project manager is available to work part-time, but is not needed.
In Figure 10 our schedule is back in the pre-leveled state.
To better understand the leveling feature, let’s increase the max percent to over-allocate resources to 100%, Figure 10. This of course means you will have one resource working 16-hour days, not realistic. However, when we level the schedule, Figure 11, note that write safety plan remains fixed.
This is because the first available cavity date starts on Monday, September 5th, the original start date of the write safety plan activity.
In one last exercise we adjust the preserve minimum float to 0-hours, Figure 12.
This time Primavera P6 Professional skips over the original available cavity date and the available cavity date starting on Thursday, and commences on Monday, September 12th, Figure 13.
So the important takeaway is that Primavera P6 wants to remove the resource over-allocation, even if it is allowable. However, if P6 cannot completely remove the over-allocation then it will schedule the respective activity to commence on the first available cavity date.
Resource allocation can be a challenging project management effort. To prepare for coordination of resources you will want to bracket the impact of resource leveling.
Inform your sponsors of the project completion date based on a completely resource-leveled schedule. This is the resource managers preferred situation. Note the schedule completion date with no resource leveling. This is usually an unrealistic situation that stretches your resources too thinly.
To find a realistic completion date that is more acceptable, level resources only within the total float. When you do this in Primavera P6 Professional be aware of your options:
1) A minimum float to preserve, i.e. buffer
2) A max percent to over-allocate resources, i.e. max overtime
Also, be aware, as demonstrated, that Primavera P6 commences the respective activity on the first available/allowable cavity date, unless provided the opportunity to completely remove the resource over-allocation.