Critical Path Method scheduling analysis appears in a significant percentage of construction disputes involving delay claims. Attorneys who understand the basics of CPM scheduling — what it measures, what it can and can’t prove, and where expert testimony is essential — are better equipped to develop delay claims and defend against them.
What CPM Scheduling Actually Shows
A CPM schedule models the sequence and duration of construction activities and identifies which sequence of activities determines the overall project duration — the critical path. Activities not on the critical path have float — time by which they can slip without affecting the completion date. Activities on the critical path have no float; a day of delay to a critical activity is a day of project delay.
The As-Planned vs. As-Built Problem
The central analytical challenge in delay disputes is comparing the as-planned schedule (what was supposed to happen) to the as-built record (what actually happened). A critical path delay analysis expert uses various methodologies — impacted as-planned, collapsed as-built, time impact analysis, windows analysis — to make that comparison and attribute delays to their causes.
Each methodology has different data requirements and different vulnerabilities under cross-examination. An expert who can explain why the chosen methodology is appropriate for the available data and defend it against alternative approaches is significantly more valuable than one who simply runs a schedule analysis without engaging with methodology.
Baseline Schedule Issues
The baseline schedule — the contractually-approved schedule against which the project is measured — is often the first contested issue in delay litigation. Questions about whether the baseline was realistic, whether it was properly updated, and whether schedule updates preserved the as-built record are frequently dispositive. The Associated General Contractors of America scheduling guide provides industry guidance on scheduling practices that serves as a useful reference point for these disputes.
What Schedules Don’t Prove
CPM analysis can establish a sequence of events and their timing with reasonable precision. It cannot, by itself, establish causation or responsibility. The expert’s schedule analysis must be combined with factual analysis — correspondence, meeting minutes, RFIs, daily reports — that links specific events to specific parties and their contractual obligations.
