Resource Levelling

Resource optimization is a very important step while preparing a project schedule. When a schedule is prepared, the team will calculate the resource requirements for each activity and for each time period of the project schedule. There will be a number of tasks which may be scheduled to run in parallel, thereby increasing the resource requirements for those time periods.  We prepare a resource loading table and resource histograms for different time periods (stages) in the project taking into account all the parallel tasks running.

Before we can finalize and publish the project schedule, the team needs to have a confirmation of availability of the planned resources for each time period as calculated in the resource loading table. An example of a planned resource requirement and corresponding resource loading are shown below.

In the above example, the resource demand is more in the months of Mar, Apr and May in comparison to other months. This is because of more tasks may be scheduled during these months.

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. Examples of resource optimization techniques that can be used to adjust the schedule due to demand and supply gap of resources include:

• Resource Levelling: This technique applies when a schedule has already been produced but one of the following problems exists with resources:
• There are fewer resources available than the schedule requires
• Certain resources are only available at specific times
• Resource usage needs to be kept at a constant level

When any of these resource constraints exist, the goal is to balance demand for resources with the available supply. The most popular response is as follows:

• In time periods with too much work for the available resources, some of the work may be moved into other time periods. This is often done by moving tasks with available positive float. This guideline or rule of thumb is referred to as a “heuristic” by some people.
• Resource levelling tends to result in a project duration that is longer than originally planned because of working with a resource constraint
• Resource Smoothing: Conceptually similar to resource levelling, you must operate within predefined resource constraints or limits. The difference is that, with smoothing, activities must be performed within the available float. The schedule is not allowed to slip. Therefore, it may not be possible to optimize all resources.

Conclusion

While optimizing resources, by using either resource levelling or resource smoothing, we make use of tasks with available positive float. The tasks with positive float can be moved forward or backward to time periods where the resource loading is less to balance the resource demand and resource availability. This is a very important step before project schedule can be published.