PERT vs. CPM orientation: Which statement correctly distinguishes the orientation of PERT and CPM techniques?

Introduction / Context:
PERT and CPM are classic network-based planning tools. Understanding their focus helps practitioners select the right tool for uncertain R&D-type projects vs. repetitive construction with known activity durations.

Given Data / Assumptions:

• PERT uses probabilistic time estimates and focuses on events (milestones).
• CPM uses deterministic durations and focuses on activities and their costs.
• Both depict logic but differ in emphasis and data requirements.

Concept / Approach:
PERT charts were historically 'event-oriented,' indexing nodes as events and computing expected times using optimistic, most likely, and pessimistic estimates. CPM, developed for construction/maintenance, is activity-oriented with cost–time trade-off (crashing) emphasis.

Step-by-Step Solution:
Identify PERT: events (nodes) mark the completion of preceding activities; uncertainty modeled with beta assumptions.Identify CPM: activities (arrows/bars) with deterministic durations; cost-curves enable crashing.Therefore, the correct distinguishing statement is that PERT is event-oriented.

Verification / Alternative check:
Most textbooks contrast Activity-on-Arrow PERT diagrams (event emphasis) with Activity-on-Node CPM diagrams (activity emphasis), even though modern software often uses AON for both.

Why Other Options Are Wrong:

• Options B, C, and D contradict standard definitions.
• Option E is incorrect: CPM includes cost optimization; PERT focuses on time under uncertainty, not cost.

Common Pitfalls:
Assuming PERT and CPM are interchangeable; ignoring that risk buffers and three-time estimates are central to PERT but not CPM.

Final Answer:
Programme Evaluation and Review Technique (PERT) is event-oriented