HKSM

In critical path method (CPM), the Late Finish Date is the latest time an activity's remaining work can be completed without moving the project completion date, as determined by the schedule network logic and any schedule constraints.

Key Points

• Calculated during the backward pass of CPM analysis.
• Driven by network logic, the required project finish date, and any constraints or deadlines.
• For activities on the critical path, LF equals EF (total float is zero).
• Total float can be computed as LF - EF (equivalently LS - ES).

Example

A project must complete by day 60. The backward pass shows Activity D has LF = day 40. If Activity D finishes after day 40, the project would slip past day 60, so day 40 is its latest allowable finish without delaying the overall completion.

PMP Example Question

While performing a backward pass, the team wants to find the latest date Activity X can finish without delaying the project finish. Which value are they determining?

1. Early Finish Date (EF)
2. Late Start Date (LS)
3. Late Finish Date (LF)
4. Free Float

Correct Answer: C — Late Finish Date

Explanation: LF is the latest permissible finish for an activity based on the schedule network, project completion date, and any constraints, identified during the backward pass.