How does the critical chain differ from the critical path?

It considers both task and resource dependencies

It considers task dependencies only

In CCPM, what happens to safety time in individual tasks?

It is removed and pooled as buffers

It is eliminated with no buffer at all

Where is a feeding buffer placed?

Where a non-critical chain joins the critical chain

At the end of the critical chain

What is 'Student syndrome' in the context of padded estimates?

Starting a task late because there appears to be time

Finishing early and reporting early

Work expanding to fill the time

Year not given

Critical chain technique

Short answer

Critical chain scheduling modifies the critical path by accounting for resource constraints and uses buffers to protect the project end date. It removes safety from individual tasks, pools it into project and feeding buffers, and manages by monitoring buffer consumption instead of task deadlines.

What do you mean by critical chain techniques?

Critical chain scheduling (CCPM) is a schedule network analysis technique, developed by Eliyahu Goldratt (Theory of Constraints), that modifies the project schedule to account for limited resources and uncertainty. It is applied to the critical path method but focuses on resource constraints and uses buffers to protect the end date.

Key ideas

Traditional estimates include hidden safety (padding) in every task. People waste it through Student syndrome (starting late), Parkinson's law (work expands to fill time) and multitasking.
CCPM removes safety from individual tasks (uses 50% probability estimates) and pools it at the end as a buffer.
The critical chain is the longest chain of dependent tasks considering both task dependencies and resource dependencies.

Types of buffers

Buffer	Placed	Protects
Project buffer	At the end of the critical chain	Project completion date
Feeding buffer	Where a non-critical chain joins the critical chain	Critical chain from delays in feeding paths
Resource buffer	Alert before the critical task	Resource availability

Critical chain:  [A]--[B]--[C]--[D]--(Project buffer)
Feeding chain:   [E]--[F]--(Feeding buffer)--^ joins at C

Steps

Build the network with dependencies.
Estimate task times with 50% chance duration (aggressive).
Resolve resource conflicts by levelling.
Identify the critical chain.
Add project and feeding buffers (typically 50% of the removed safety).
Track using buffer consumption (green, yellow, red zones).

Advantages

Shorter and more reliable schedules.
Reduces multitasking and waste of safety.
Focuses management on the constraint.

Limitations

Needs cultural change; estimates are difficult; not suited to all projects.

Critical path	Critical chain
Task dependencies only	Task and resource dependencies
Padding in tasks	Pooled buffers
Float management	Buffer management

Example: A software release with a few shared testers uses a project buffer of 10 days instead of adding 2 days to each task.

✓ Answer checked by Claude Opus 5.5 (high effort)

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