Baseline and Current Schedules
Establishing a baseline schedule is essential to effective management. A baseline schedule represents the original configuration of the program plan and signifies the consensus of all stakeholders regarding the required sequence of events, resource assignments, and acceptable dates for key deliverables. It is consistent with both the program plan and the program budget plan and defines clearly the responsibilities of program performers. The baseline schedule includes not only original forecasts for activity start and finish dates but also the original estimates for work, resource assignments, critical paths, and total float.
The baseline schedule is not the same as the current schedule. The current schedule is updated from actual performance data, as described in Best Practice 9. Therefore, it is the latest depiction of performance and accomplishments, along with the latest forecast of remaining dates and network logic. The baseline schedule represents the program’s commitments to all stakeholders, while the current schedule represents the actual plan to date.
The current schedule is compared to the baseline schedule to track variances from the plan. Deviations from the baseline inform management that the current plan is not following the original plan all stakeholders have agreed to. Deviations imply that the current approach to executing the program needs to be altered to align the program to the original plan or that the plan from this point forward should be altered.
Comparing the current status of the schedule to the baseline schedule can help managers identify the cause of the deviation, thereby allowing them to target specific areas such as resource assignments, network logic, and other factors for immediate mitigation. Without a formally established baseline schedule to measure performance against, management lacks the ability to identify and mitigate the effects of unfavorable performance.
The final version of the current schedule—the “as-built” schedule—represents the plan as executed to completion. Particular care should be taken to archive this final version. Once the project has been completed, the as-built schedule becomes a database of the actual sequence of events, activity durations, required resources, and resource productivity. These can be compared to the original plan for an assessment of lessons learned, and the data become a valuable basis of estimate input for schedule estimates of analogous projects.
As-built schedules are also useful for creating and validating fragmentary networks, or “fragnets.” A fragnet is a subordinate network that represents a sequence of activities typically related to repetitive effort. Subordinate networks can be inserted into larger networks as a related group of activities. For example, a related group of activities may occur for each systems test, regardless of the actual product. In this case, a fragnet related to systems test, representing a well-known sequence of events and expected duration, may be inserted into various product schedules.
The baseline should be set promptly after a program begins. A schedule baseline is typically in place between 3 and 6 months of contract award, although the timing depends on contract size and type, requirements, and risk.42 Projects should operate on an interim schedule until the schedule baseline is in place. The level of detail in the baseline schedule also depends on contract type, industry type, risk, and agency guidelines. For example, management may choose to baseline the entire detailed IMS or only intermediate-level summary activities leading to key milestones. The greater the baselined detail is, the greater will be the understanding of performance, variances, forecasts, and assessed effects of potential changes—yet this must be balanced with the time necessary to formally approve, change, and track at that level.
In addition, baseline creation and approval may take place in concert with the program’s rolling wave process. That is, as periods of summary and intermediate-level planning packages are planned in greater detail, the baseline is updated to reflect that detail. The intent is that once formally approved and archived, the baseline schedule reflects the agency’s commitment to allocating resources and becomes the basis against which actual performance and accomplishments can be measured, monitored, and reported. The parties should agree that the baseline refers to the maintenance of a schedule for meeting contractual deliverable and program control milestones. It typically does not constitute a strict adherence to estimates of activity durations, resource assignments, or logic.
Establishing and maintaining a schedule baseline is highly significant when EVM is a requirement. Appendix III has more information.↩︎