Network scheduling terminology (PERT/CPM): The start or completion of a task (with no duration itself) is called a(n) ________.
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AEvent
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BActivity
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CDuration
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DNone of these
Answer
Correct Answer: Event
Explanation
Introduction / Context:PERT/CPM models represent projects as networks of activities and events. Correct terminology is essential for reading and building these networks.
Given Data / Assumptions:
- Activities consume time and possibly resources.
- Events (nodes) mark the start or finish of activities and have zero duration.
- Precedence relationships connect events via activities.
Concept / Approach:In activity-on-arrow (AOA) or activity-on-node (AON) representations, the notion of a milestone (event) captures the instant a state is achieved (e.g., “foundation complete”). It has no time span; activities carry duration.
Step-by-Step Solution:
Identify whether the item consumes time → if yes, it is an activity.If it is an instantaneous marker of start/finish with zero duration → it is an event.Therefore, “start or completion of task” is an event.Verification / Alternative check:Network definitions: nodes/milestones/events have zero duration; arcs/activities have positive duration.
Why Other Options Are Wrong:(b) Activity always has duration; (c) duration is a quantitative attribute, not an object; (d) contradicts standard definitions.
Common Pitfalls:Using “activity” and “event” interchangeably; assigning duration to events.
Final Answer:
Event