Capacity Expansion Cases

This lesson teaches how to decide whether, when, and how a client should add capacity.

Why This Matters

Capacity expansion cases test whether you can make a forward-looking decision under uncertainty.

They require you to balance:

• demand outlook
• economics
• timing
• utilization risk

The Case Pattern

The central question is usually:

• should the client expand capacity?

To answer that, you need to determine:

• whether demand will justify the additional capacity
• whether the economics are attractive
• whether the risk of under- or over-capacity is acceptable

What the Interviewer Is Testing

These cases often look simple but contain important timing logic.

Do not just compare today’s demand with today’s capacity. Consider:

• forecast demand
• ramp-up time
• flexibility of the investment
• downside risk

How to Approach It

1. Clarify the decision

Determine:

• how much capacity is being considered
• when it would come online
• whether there are alternative ways to serve demand

2. Forecast demand

Estimate:

• base demand
• growth rate
• seasonality or peak effects
• uncertainty range

3. Assess current and future utilization

Ask:

• where is the system constrained today?
• when will the capacity become binding?

4. Assess economics

Consider:

• capex
• operating cost
• margin from additional volume
• payback or return logic

5. Assess options and risk

Compare:

• full expansion
• phased expansion
• outsourcing
• yield management / pricing
• process improvement

Case Example

Prompt:

"A manufacturer is considering adding a new production line."

A strong candidate would assess:

• whether projected demand truly exceeds effective capacity
• whether process improvements could delay the need
• economics of the new line
• downside risk if demand underperforms

What Strong Candidates Do

A strong candidate:

• treats the problem as a future decision, not a current snapshot
• uses demand scenarios
• compares expansion with alternative solutions
• makes a timing-conscious recommendation

What Weaker Candidates Tend to Do

A weaker candidate often:

• assumes high utilization means immediate expansion
• ignores uncertainty in demand
• forgets capex and payback
• overlooks flexible alternatives

Common Traps

Mistake 1: Ignoring effective capacity

Nominal capacity and usable capacity are not always the same.

Mistake 2: Recommending expansion too early

The client may be able to defer the investment through process changes or pricing.

Mistake 3: Ignoring downside risk

Overcapacity can damage returns for years.

Practice Prompt

An airline expects passenger growth on a major route. What would you examine before recommending more aircraft capacity?

Example Approach

"I would first clarify the size, timing, and irreversibility of the capacity decision. Then I’d forecast demand under a few scenarios, compare it with effective rather than theoretical capacity, and evaluate whether the added volume would justify the investment economically. I would also compare full expansion with alternatives such as outsourcing, process improvements, or a phased build before making a recommendation."

What to Remember

• Capacity expansion cases are timing and risk decisions.
• Forecast demand carefully and compare it with effective capacity.
• Evaluate economics and downside risk, not just growth potential.
• Flexible or phased alternatives often matter.