Delay Analysis Methods
Windows Analysis (Time Slice Analysis)
Windows analysis divides a project's timeline into consecutive periods -- usually matching real schedule updates -- and separately identifies what was driving the critical path and how many delay days occurred within each one.
Definition
Rather than comparing only the original baseline against the final as-built schedule, windows (or time slice) analysis examines a project window by window, typically bounded by the updates that actually exist. Within each window, the analyst identifies the contemporaneous critical path and attributes any delay occurring during that period to a specific cause. This retrospective, observational approach reveals patterns -- gradual erosion versus a single sharp event -- that a single before/after comparison can't distinguish, since both could show the identical total swing in float or finish date.
Example
A 210-day project is split into four windows bounded by its quarterly updates; each window's critical path and delay-day total are identified separately, then summed to produce the project's full delay history rather than just its net result.