Resource Leveling VS Resource Smoothing

Resource Leveling and Resource Smoothing are two popular Resource Optimization techniques.

Resource Optimization questions are frequently seen in the PMP exam. So it is important to be clear in this topic..

In the real world, it is quite rare that a project has all the resources it needs as per the schedule. If you are fortunate enough to have all the resources you need for your project, do not take them for granted as any risk during project execution can leave you with less than desirable resources. Further, even though you have all the resources you need for the entire duration of the project, as a responsible Project Manager it is your duty to use the available resources efficiently. This is where Resource Optimization comes in.

What is Resource Optimization ? 

In simple words, it is finding ways to adjust the use of resources that is most cost-efficient or that results in highest performance.

PMBOK says that Resource Optimization is used to adjust the start and finish dates of activities to adjust planned resource use to be equal to or less than resource availability. 

There are 2 parts to the PMBOK explanation of Resource Optimization above

1. Adjusting Start and Finish dates of activities
2. Resource use to be less than or equal to resource availability.

So it basically says, use only the resources available for your project (do not bring in additional resources), and if they are insufficient, then adjust the start and finish dates of activities on which these resources work.

The objectives of resource optimization are achieved by using Resource Optimization techniques. There are 2 popular ones

1. Resource Leveling
2. Resource Smoothing

Resource Leveling

In order to complete the project with a limited amount of resources, you lengthen the project schedule. 

Resource leveling is sometimes called Resource Constrained Scheduling (RCS). If resources are not available, the overall project duration may change, mostly it extends. 

Resource leveling is extending the project schedule to complete the project with the available limited resources.

Resource Leveling Example

Example: You have 10 days to complete your project, and you require 10 resources working full time for 10 days to complete the project. But you have only 6 resources available. What will you do?

With Resource Leveling, you extend the project schedule. Your 6 resources will work for the first 10 days, and then these 6 resources are again employed to work on the remaining work to complete the work.

So, in this process, No Additional resources are not used, Project is completed, but the project schedule is extended. There is a change in the critical path of the project.

When to use Resource Leveling?

• When Critical or shared resources are only available for a limited amount of time.
• When the available Critical or shared resources are insufficient.
• When resources are over-allocated.
• When you want to keep the resource usage at a constant level.

Resource Smoothing 

Resource Smoothing is doing resource leveling only within the limits of the float of their activities. The overall project schedule duration is not changed. 

Project activities may only be delayed within their free and total float. 

Unlike Resource Leveling, which may result in a change in the critical path, Resource Smoothing does not result in changes to the critical path. 

Resource Smoothing may not be able to optimize all the resources, because the activities on the critical path do not have a float, so Resource Smoothing cannot be done on activities on the critical path.

Time is the main constraint here, and you have to optimize your resource within the available duration. That is why Resource Smoothing is also called Time Constrained Scheduling (TCS).

Resource Leveling vs Resource Smoothing