Critical Path Length Index (CPLI)

DCMA considers a CPLI below 0.95 to be indicative of a potential problem requiring further investigation and possible mitigation.

The Critical Path Length Index (CPLI) is a project in-progress measure of the level of efficiency needed to complete the project.

During the construction phase the works are often either ahead or behind schedule by varying amounts.  This test is intended to provide an indicator index for the safety margin on hitting the baseline due date for completion.

It is calculated by taking the remaining days duration shown on critical path, adding or subtracting number of days total float ahead or behind the baseline finish date, and then dividing the sum by the remaining days duration to provide a CPLI Index Factor.  The Index becomes more telling as the project progresses and the number of remaining days reduces. The following examples should clarify the calculation process.

Example 1: Programme running on time

A CPLI of 1.00 indicates that the project is currently on time but must perform exactly to plan for the remainder of the project with no margin for error or delay.

Example 2: Programme running 2 days ahead

A CPLI above 1.00 indicates that there is remaining schedule margin.  The higher the number the higher the margin of safety.  This example indicates a 2% safety margin on time.

Example 3: Programme running 3 days behind

CPLI below 1.00 indicates that the construction team must overachieve on the remaining works in order to meet the baseline finish date. This example indicates minus 3% safety margin on time