Class 111: Update Schedules

November 19, 2021 0 Comments


What happens when project events occur that were not accounted for in the baseline schedule? Construction projects are complex and changes are common. Therefore, project schedules are updated on a regular basis, typically monthly, to account for project progress and update plans for future work. AACEI states a project schedule update is “a statused, dynamic version of the baseline schedule that reflects the most current information on the project.”1

Example of an Update Schedule:

The example above shows a typical construction schedule for a high-end mixed-used skyscraper. The construction schedule has been updated to reflect the current status of the project. In the gantt chart, the blue bars identify activities that are complete. The green bars represent forecasted activities that are not on the critical path, while the red bars identify forecasted activities on the critical path. Yellow bars identify the baseline schedule activities.  Without updates to the construction schedules, project stakeholders would not have a concise understanding of the current project status as compared to the original plan. Thus, update schedules provide the ability to adjust deliveries, resources, and finances to account for project events impacting the schedule.  

Why are Update Schedules important?

On very large construction projects, changes occur frequently.  Project owners can issue change orders, subcontractors can fall behind schedule on their work and weather events can impact a project. Regularly updated schedules document the events that occur during the life of a project and allow quick assessment of its impact. This creates an opportunity to mitigate potential future issues. 

Additionally, schedule updates are often used as the backbone for forensic delay analysis when analysts work to determine the root cause and quantification of project events. When regularly updated, schedule updates can be a useful archive of a project’s execution.

Schedule Update Summary:

1. Schedule updates can provide the status of a project.

2. Schedule updates can incorporate progress delays, change orders, and other events impacting the project.

3. In forensic delay analysis, schedule updates provide a history of project events.

Key Terms:

Construction Schedule comprehensive and realistic plan that represents the specific activities, reasonable duration for the activities, and the planned sequence of work for the project

Baseline Schedule static project schedule that reflects all formally authorized scope and schedule changes against which the project performance is measured

Gantt Chart a type of bar chart that provides a graphical representation of a schedule that includes the activities that make up a project  




1.      AACE International Recommended Practice.  91R-16 Schedule Development.

2.      AACE International Recommended Practice.  10S-90: Cost Engineering Terminology.