Overview
Resource Leveling is performed to balance the demand and supply of resources (resource limitations). Resource Smoothing is performed to achieve a more uniform resource utilization over a period of time.
Resource Leveling may change the critical path, but Resource Smoothing does not.
Resource Leveling optimizes the resource utilization, but Resource Smoothing may not.
If you have over allocated resources, you would perform resource leveling. If you have non-uniform resource allocation or if you have constraints on the maximum number of resources, you would perform resource smoothing.
Examples
Resource Leveling
For example, Sam is allocated 200% on the project for the first month. Obviously, you don’t want to overload your people (that’s bad project management or an anti-PMIism, if there’s such a term). Therefore, you would perform resource leveling to ensure that no resource is allocated more than 100% at any point during the project.
Before resource leveling
| Month 1 | Month 2 |
| Sam - 200% Mark - 100% | Sam - 100% Mark - 100% |
After resource leveling
| Month 1 | Month 2 | Month 3 |
| Sam - 100% Mark - 100% | Sam - 100% Mark - 100% | Sam - 100% |
Note that the project has been extended by a month.
Resource Smoothing
You are using eight resources in month 1, two in month 2, and four in month 3. However, due to funding limit constraints, you are only allowed to use a maximum of five resources in any month.
Before resource smoothing
| Month 1 | Month 2 | Month 3 |
| 8 | 2 | 4 |
After resource smoothing
| Month 1 | Month 2 | Month 3 |
| 5 | 4 | 5 |
Note that the project duration did not change.