Issue Trees

This lesson teaches how to use issue trees to break broad business problems into manageable analytical branches.

Why This Matters

Issue trees are one of the most practical tools in case interviews.

They help you:

• organize a messy problem
• make your structure easier to follow
• decide what to analyze first
• avoid random wandering through the case

Without a usable issue tree, many cases quickly become unfocused.

The Underlying Logic

An issue tree is a visual or mental decomposition of a problem into smaller parts.

At the top sits the main question.

Under that question sit the key branches that explain or determine the answer.

A strong issue tree:

• is driven by the client problem
• has clear branches
• is easy to use in live conversation

It does not need to be beautiful. It needs to be useful.

In a Live Case

When you hear a broad prompt, your first structure is often an issue tree in spoken form.

For example:

• if profit is down, break into revenue and costs
• if growth is slow, break into market, customer, product, and commercial levers
• if entry is uncertain, break into attractiveness, economics, capabilities, and risk

The tree helps you decide where to go first and what data would matter.

How to Work Through It

1. Put the main question at the top

Examples:

• why are profits down?
• should the client enter this market?
• how can the client grow?

2. Choose the first-level branches

These should be the major drivers of the answer.

3. Expand only where needed

You do not need to build a deep tree for every case.

Expand the branches that are most likely to matter.

4. Keep the branches decision-relevant

Every branch should help answer the top question.

5. Use the tree to guide your next move

The tree is not a static object. It should help you prioritize the analysis.

Example

Question:

“Why are profits down for this restaurant chain?”

A basic issue tree could be:

• revenue
  • traffic
  • average spend
  • mix
• costs
  • food cost
  • labor cost
  • occupancy cost

That tree is not the full answer, but it gives you a practical map.

What Strong Candidates Do

A strong candidate:

• builds a tree that matches the problem
• uses the tree to guide analysis
• avoids unnecessary complexity
• updates the tree mentally as new evidence arrives

What Weaker Candidates Tend to Do

A weaker candidate often:

• uses branches that are too vague
• expands everything equally
• creates trees that sound smart but do not guide action
• forgets to prioritize once the structure is done

Common Traps

Mistake 1: Building a tree that is too shallow

If your branches are too broad, they do not help much.

Mistake 2: Building a tree that is too deep

If you over-expand every branch, you may lose speed and clarity.

Mistake 3: Using generic branches without a business reason

A tree should reflect how the problem actually works.

Mistake 4: Treating the tree as the end product

The point is not to present a tree. The point is to solve the case with it.

Practice Prompt

Take this question:

“Should a fitness app raise prices?”

Write a simple issue tree with three to four top-level branches.

Then decide which branch you would investigate first and why.

Example Response

A useful spoken structure might sound like this:

I would break this problem into three main areas: first, the customer side, including willingness to pay and churn risk; second, the economic side, including current margins and pricing power; and third, the competitive side, including likely market response. I would start with the customer and economic branches because they most directly determine whether a price increase is viable.

What to Remember

• Issue trees are a practical way to decompose broad business questions.
• A good issue tree is clear, relevant, and easy to use.
• The tree should help you choose where to analyze first.
• The goal is not complexity. The goal is useful structure.