Most project managers realize that the critical path method and the PERT technique Do not consider resource availability.
So, the first thing that needs to happen after you have pulled together a schedule of activities and determined the critical path, is to plug in resources for those activities and adjust the schedule, or resources, according to any resource constraints you discover.
You will have identified resource estimates during the Estimate Activity Resources process.
So now, during the Develop Schedule process, resources are assigned to specific activities.
Usually, you will find that your initial schedule has periods of time with more activities and you have resources to work on them. In addition, you will find that it is not always possible to assign 100% of your team members time to tasks.
Another snag you will discover, is that your schedule will show a team member who is over-allocated – Meaning that they are assigned to more work than they can physically perform within the given time.
But the reverse can be true as well, they may not be assigned enough work to keep them busy during the time period.
This problem is easy to fix. You can assign under allocated resources to multiple tasks to keep them busy.
However, adjusting the schedule for over-allocated resources is a harder problem to fix.
There are three techniques that optimize resources to prevent over allocation where possible:
All three of these techniques should be used with critical path method-based schedules.
This is also called resource based methods, and is used when resources are over to allocated, when they are only available at certain times, or when they are assigned to more than one activity at a time.
In a nutshell, resource leveling attempts to balance out the resource assignments to get tasks completed without overloading the individual.
You will accomplish this by adjusting the start and finish dates of schedule activities based on the availability of resources.
This typically means allocating resources to critical path tasks first, which often changes the critical part of and, in turn, the overall project end date.
The project manager can accomplish resource leveling in two other ways as well.
You might delay the start of a task to match the availability of a team member, or you might adjust the resource assignments so that more tasks are given to a team members who are under-allocated.
Most times, resource leveling of over allocated team members extends the project end date.
If you are under date constraint, you will have to rework the schedule off for assigning resources to keep the project on track with the committed completion date. You can accomplish this with resource smoothing, which I will now describe:
Resource smoothing accommodates resource availability by modifying activities within their float times without changing the critical path or project end date.
This means you will also use this technique when you need to meet specific should rule dates and are concerned about the resource availability.
There are several ways you can accomplish this.
There are two other approaches that you might consider:
Reallocating those team members with slack time to critical path tasks to keep them on schedule is another option. Do not forget, fast tracking is another way to keep the project on schedule.
This is a technique used when key resources, like a subject matter expert for example, are required at a specific point in the project and they are the only resource available to perform such activities due to their unique skills.
This technique requires the resources to be shed ruled in reverse order. What this means is, from the end date of the project rather than from the beginning, to assign this key resource at the correct time.
Resource leveling can cause the original critical path to change and can delay the project’s completion date.
Resource smoothing modifies activities within their floats without changing the critical parts or project end date.
It is used when changes to the critical part cannot or should not be made. Reverse resource allocation scheduling is used when specific resources are needed at certain times.