The earliest time an activity can begin after all predecessors are completed.

The earliest time an activity can begin after all predecessors are completed.

• A. Latest Finish (LF)
• B. Earliest Finish (EF)
• C. Earliest Start (ES)
• D. Latest Start (LS)

Answer: (C)

This item tests how to determine the start of an activity in a project network. The earliest start time is the earliest moment the activity can begin once all its predecessors are finished. Since you must wait for every predecessor, you take the latest completion among them. So ES equals the maximum finish time of all predecessors. For example, if one predecessor finishes at time 5 and another at time 9, the activity can start at 9; if its duration is 3, its earliest finish would be 12. The other timestamps refer to different things: earliest finish depends on the start time plus duration, latest start is the latest time you can begin without delaying the project, and latest finish is the latest time the activity can finish without delaying the project.

This item tests how to determine the start of an activity in a project network. The earliest start time is the earliest moment the activity can begin once all its predecessors are finished. Since you must wait for every predecessor, you take the latest completion among them. So ES equals the maximum finish time of all predecessors. For example, if one predecessor finishes at time 5 and another at time 9, the activity can start at 9; if its duration is 3, its earliest finish would be 12. The other timestamps refer to different things: earliest finish depends on the start time plus duration, latest start is the latest time you can begin without delaying the project, and latest finish is the latest time the activity can finish without delaying the project.