Schedule Quality
CPLI (Critical Path Length Index)
CPLI measures whether a project's critical path is getting longer relative to baseline, calculated as (Critical Path Length + Total Float) / Critical Path Length.
Definition
Critical Path Length (CPL) is the calendar-day span from the baseline schedule's data date to its finish date. Total float (TF) is pulled from the current update's finish activity. CPLI = (CPL + TF) / CPL. A value of 1.0 means the project is tracking exactly to its baseline finish; a value below roughly 0.95 -- a commonly cited floor, not an official DCMA pass/fail line -- suggests the critical path has stretched out relative to plan. DCMA literature actually documents more than one CPLI formula, so this is one defensible, transparent reading rather than the only correct one. CPLI's real value is as a trend indicator, not a single-update snapshot: a CPLI sliding from 1.0 toward 0.9 across several consecutive updates is evidence the project's finish exposure is growing, often visible before any specific activity has crossed into negative float or started actively driving the finish date.
Example
A project's baseline critical path length is 400 calendar days. The current update shows the finish activity carrying 20 days of total float: CPLI = (400 + 20) / 400 = 1.05, indicating the project is currently tracking slightly ahead of its baseline critical path.