Brainstorming in Cases

This lesson teaches how to brainstorm in a structured, commercially sensible way during case interviews.

Why This Matters

At some point, many cases shift from analysis to ideation.

The interviewer may ask:

• How could the client grow revenue?
• What could reduce churn?
• How might the company cut cost?

Weak candidates answer with random ideas.

Strong candidates organize their ideas into buckets and generate suggestions that are practical and relevant.

What Good Looks Like

Good brainstorming in a case is not about having the most ideas.

It is about producing ideas that are:

• structured
• distinct
• relevant to the client problem
• commercially plausible

This is why brainstorming should still feel like problem solving, not free association.

In the Interview

Before listing ideas, quickly choose a set of buckets.

For example, to grow revenue you might use:

• get more customers
• increase purchase frequency
• increase average spend

That structure helps you think clearly and helps the interviewer follow you.

A Reliable Way to Do It

1. Clarify the objective

What kind of ideas are needed?

• growth ideas
• cost ideas
• retention ideas

2. Create two to four buckets

Buckets should organize the solution space.

3. Generate ideas within each bucket

Do not just name a bucket. Fill it with actual actions.

4. Prioritize or evaluate if asked

The best candidates often move naturally from ideation to judgment.

5. Tie ideas back to the client context

A good idea for a budget airline may be bad for a luxury hotel.

Example

Prompt:

“How could a hotel chain increase utilization?”

A weak brainstorm:

• lower prices
• do marketing
• improve service
• expand locations

A stronger brainstorm:

“I would think about utilization in three buckets. First, increase demand from existing target customers, for example through weekday promotions or loyalty offers. Second, attract new segments, such as corporate events or extended-stay guests. Third, improve channel performance, such as better partnerships with travel platforms or direct-booking incentives.”

That answer is more structured, more distinct, and easier to build on.

What Strong Candidates Do

A strong candidate:

• groups ideas into clean buckets
• offers ideas with business logic
• adjusts ideas to the client context
• avoids overlap

What Weaker Candidates Tend to Do

A weaker candidate often:

• blurts out disconnected suggestions
• repeats similar ideas in different words
• gives generic actions with no mechanism
• forgets to connect ideas to the objective

Common Traps

Mistake 1: Random list-making

Unstructured ideation sounds chaotic.

Mistake 2: Buckets without ideas

Naming categories is not enough.

Mistake 3: Ideas without business logic

“Do more marketing” is not a useful idea unless you explain what it is meant to achieve.

Mistake 4: Forgetting prioritization

If asked, you should be able to say which ideas are best and why.

Practice Prompt

Brainstorm ways for a digital bank to grow customer deposits.

Group your answer into three buckets and list one or two ideas per bucket.

Example Response

A strong transition into brainstorming might sound like this:

I would like to group the ideas into three buckets so the solution space stays organized: first, actions to attract more customers; second, actions to increase frequency or usage among existing customers; and third, actions to improve economics through better pricing or packaging.

What to Remember

• Good brainstorming in cases is structured and practical.
• Use buckets before listing ideas.
• Make sure ideas are distinct and relevant to the client problem.
• Strong brainstorming often includes both ideation and judgment.