Windows Schedule Delay Analysis
A windows schedule analysis, also referred to as a "contemporaneous period schedule analysis," is a retrospective schedule impact analysis technique that generally utilizes contemporaneous schedule updates, in conjunction with as-built facts related to a delay or change, to quantify schedule impacts to the as-built critical path associated with the change or delay. This schedule analysis takes into account the change’s or delay’s relationship to past and/or concurrent events and circumstances. The windows method relies on the forward-looking schedule calculations at the time updates were prepared which reflect the current status of the project and the contractor’s plan for project completion at various points in time. This technique allows for examination of the dynamic nature of the critical path from period to period as the project unfolds.
The windows schedule analysis typically begins with the baseline construction schedule and proceeds chronologically from update to update, tracking progress along the critical and near critical paths. For each analysis period, the prior update becomes the baseline for the analysis of delays or accelerations. The windows method compares start dates, finish dates, and duration of the activities and identifies changes to schedule logic between analysis periods. As such, implementation of the windows schedule analysis depends on reliable baseline schedule information, contemporaneous schedule updates, and as-built schedule information.
The following illustration shows the effect of critical path delays occurring during different windows, or periods, of a project schedule:
Although the windows schedule analysis is performed in a retrospective context, either shortly after a delay event occurs or after the completion date of the entire project, it is not a hindsight analysis approach. Rather, the windows schedule analysis is a forward-looking technique because the analysis generally proceeds from the beginning of a project and moves forward in time on a chronological and cumulative basis. The windows schedule analysis evaluates as-built performance information and records to determine whether delays or changes actually delayed the critical path of a project.
It should be noted that there are several important considerations for choosing an appropriate schedule analysis methodology. Each claim is unique and deals with different contract requirements, situational contexts, levels of documentation, complexities, legal jurisdictions, and dispute resolution forums, among other factors. The selection of a particular schedule analysis method should be based on professional judgment and diligent factual research and evaluation. Interface Consulting has extensive experience handling construction delay claims, and our construction claims consultants are skilled at tailoring our schedule analysis approach based on project needs and constraints.