Critical Path Length Index (CPLI)

What it is

The Critical Path Length Index measures how realistic it is to finish the project on time,
given the work left on the critical path. It is check #13 of the DCMA 14-Point Assessment.

CPLI compares the remaining length of the critical path with the time actually available to
complete it. A value of 1.0 means the critical path fits exactly within the time left. Below
1.0, the remaining work needs more time than is available, and the team must perform
better than planned to meet the target date.

How it's calculated

CPLI = \frac{\text{Critical Path Length} + \text{Total Float}}{\text{Critical
Path Length}}

Critical Path Length is the number of working days from the data date to the forecast
project completion. Total Float is the float of the critical path measured against the target
completion date, such as the baseline or contract finish. When the forecast finish is later
than the target, that float is negative and CPLI drops below 1.0

For example, a project has 100 working days of critical path remaining and is forecasting a
finish 10 working days past its target. CPLI = (100 − 10) ÷ 100 = 0.90. The team would need
to complete 100 days of critical work in 90 days, a 10% improvement over the current plan.

Why it Matters

CPLI turns a slip into a measure of effort. Ten days of delay with two years of work
remaining is very recoverable; the same ten days with a month remaining is not. Tracking
CPLI across updates shows whether the remaining path is getting harder or easier to
achieve, which points to when recovery action is needed.

DCMA Acceptance Criteria

CPLI should be 0.95 or greater. A value below 0.95 indicates the project is unlikely to meet
its target completion without recovery measures. A value above 1.0 means the critical
path has time to spare.

Related SmartPM Metrics

SmartPM already tracks critical path health and the activity-level delays that erode it.
CPLI differs because it rolls those effects into one ratio, comparing the remaining critical
path against the time available to the target finish, and it is read over the schedule's
history rather than a single update.