Which method is used to calculate latest start (LS) and latest finish (LF) times?

Which method is used to calculate latest start (LS) and latest finish (LF) times?

• A. Forward Pass
• B. Backward Pass
• C. Gantt Chart
• D. CPM

Answer: (B)

Calculating the latest start and latest finish times uses a backward pass through the activity network. You start from the project’s end and work backward, setting the final activity’s LF equal to the project duration, then for each precursor you determine its LF as the minimum of its successors’ LS, and its LS as LF minus its duration. This approach shows the latest moments that won’t delay the project, revealing slack for each activity and highlighting the critical path where slack is zero. The forward pass, by contrast, computes earliest times from the start toward the end, and tools like Gantt charts visualize the schedule while CPM is the overall method.

Calculating the latest start and latest finish times uses a backward pass through the activity network. You start from the project’s end and work backward, setting the final activity’s LF equal to the project duration, then for each precursor you determine its LF as the minimum of its successors’ LS, and its LS as LF minus its duration. This approach shows the latest moments that won’t delay the project, revealing slack for each activity and highlighting the critical path where slack is zero. The forward pass, by contrast, computes earliest times from the start toward the end, and tools like Gantt charts visualize the schedule while CPM is the overall method.