Purpose

The performance baseline is also known as the performance measurement baseline (PMB). It is the metric benchmark against which project performance in terms of time and cost is measured. Project managers use the PMB to determine cost and schedule variance and to display that information in an S-curve format.

Application

The PMB is established during the planning phase, once the initial costs and schedules have been developed and approved. The PMB ideally sees little change during the project’s life, because it provides insight as to how the project was supposed to perform (versus how it actually evolved and performed). For management, it provides the ability to review the original projected spending for the project over time. For project managers, it provides a tool to later establish a sense of the relative levels of variance. For team members, it affords an objective perspective on their targets for spending over time.

Content

The PMB may take the form of a graph or spreadsheet analysis of the spending plan (Figure 4.7). It consists of incremental and/or cumulative spending projections mapped against the timeline. It can be depicted through a line graph, bar chart, or both.

The content is normally derived from the project management software package being used to construct and track the work breakdown structure, the costs of the WBS work packages or control accounts, and the timing of those work elements within the network schedule.

Approaches

The PMB may be used as a stand-alone document for historical reference, or may be coupled with actual spending information later in the project to afford some clarity on the actual spending versus the original plan. It can also be incorporated with earned value information to highlight performance in terms of work accomplished against the original plan for cost and schedule.

Considerations

Some project managers like to update their PMB regularly to accommodate the myriad changes that are inevitable on a project. While the changes may be authorized and funded, they should not be directly integrated into the baseline, because management requests for baseline information often point back to the original documentation. Questions often surface about why current spending does not match the baseline, and without the original baseline for history, it is difficult to provide meaningful responses to such inquiries.