Learn in the textbookSchedule Planning and the Arrow Diagram
DefinitionPERT is a technique that organizes a project's tasks by their order and durations to plan and manage the overall schedule.
ExplanationFor each task, you decide which tasks must finish before it (its predecessors) and how many days it needs. Drawing the result as an arrow diagram (アローダイアグラム) shows the total duration and which tasks can run in parallel. After the plan is made, it is also used to manage the schedule by revising it to match actual progress.
AnalogyIt is like planning a house move. You cannot carry anything out until it is packed, but you can file your change-of-address paperwork while you pack. Once you write down the order and the days, you can see how long the whole move will take.
Memory hookIt stands for Program Evaluation and Review Technique. The word Review in the name reminds you that it is a method for revising the plan as work moves forward.