SSI Tools for Microsoft Project

User guide


Critical Path Length Index (DCMA Point 13 - "CPLI" Assessment)

SSI Tools Counts:
All items on the Critical Path from beginning to end.  Pass/Fail test is determined by comparing the end to end duration of the critical path to the end to end duraiton of the critical path plus its float.  Positive float on the critical path contributes toward a positive score and negative float does the opposite.  If float is greater than zero the score will be greater than 1.00 and if negative float exists on the critical path the score will be less than 1.00.  Though a score greater than .95 is considered passing, a score less than 1.00 means that there is negative float somewhere in the schedule which should be resolved by Critical Path and Root Cause Analysis using SSI Critical Path Method analysis tools.
From DCMA-EA PAM 200.1 Paragraph 4.13 and
The Critical Path Length Index (CPLI) is a measure of the efficiency required to complete a milestone on-time. It measures critical path “realism” relative to the baselined finish date, when  constrained. A CPLI of 1.00 means that the program must accomplish one day’s worth of work for every day that passes. A CPLI less than 1.00 means that the program schedule is inefficient with regard to meeting the baseline date of the milestone (i.e. going to finish late). A CPLI greater than 1.00 means the program is running efficiently with regard to meeting the baseline date of the milestone (i.e. going to finish early). The CPLI is an indicator of efficiency relating to tasks on a milestone’s critical path (not to other tasks within the schedule). The CPLI is a measure of the relative achievability of the critical path. A CPLI less than 0.95 should be considered a flag and requires further investigation.
The CPLI requires determining the program schedule’s Critical Path Length (CPL) and the Total Float (TF). The CPL is the length in work days from time now until the next program milestone that is being measured. TF is the amount of days a project can be delayed before delaying the project completion date. TF can be negative, which reflects that the program is behind schedule. The mathematical calculation of total float is generally accepted to be the difference between the “late finish” date and the “early finish” date (late finish minus early finish equals total float). The formula for CPLI is as follows: Critical Path Length Index (CPLI)=CPL+TFCPL CPLI calculation.
For programs that provide the IMS in a static format, the CPL is estimated by counting workdays between the start and finish. This can also be done by creating a new project file and entering the dates in the manner described in the Critical Path Guide. Total Float used for this method is the float for the completion milestone identified on the critical path. If the IMS is not delivered in the native software tool and is not independently verified note the data used, method of verification or that verification could not be independently conducted, and method used to assess the critical path. In addition to recording the CPLI results, it is important to document any rationale for the completion milestone chosen and the analysis method used to calculate the critical path. It is also important to note if the final milestone or task in the schedule has a baseline finish date beyond the contract period of performance (CPR Format 3, Block 5.k.). 
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