How to effectively structure a case?

Question

Hey everyone,
I’m currently working on case interview structuring and my main challenge is building issue trees from first principles in the first 3–5 minutes.

More specifically, I struggle with three things:

choosing the right top-level drivers for the objective,
adapting the tree to the business model, and
knowing when to use a broader competitive/root-cause tree vs. a pure profitability tree.

For example, in a case like “grow revenue from existing telecom customers,” I often go too broad (customer/product/competitor) instead of staying close to the revenue engine (retention, ARPU, upsell). In “low-cost entrant causing margin pressure,” I’m often unsure how to structure the response cleanly.

Has anyone found good drills or exercises to improve this? Especially for identifying first-level drivers and then developing strong second-level branches without relying on memorized templates?

Answer 1

Hi Mustafa, very common challenge — and honestly what you describe is exactly the shift from “using frameworks” to actually structuring.

A few thoughts.

1. Start from the objective, not from case types
Most structuring issues come from asking:
“Which framework fits?”

Better question:
“What drives this objective mechanically?”

For your telecom example, if the objective is revenue growth from existing customers, start from the equation:

customers × revenue per customer

Then maybe:

retention
upsell / cross-sell
pricing / ARPU

Very clean.

In other words: follow the economics of the problem first, not a generic business framework.

2. Use broad root-cause trees only when the question calls for diagnosis
Simple rule I use:

If the question is improve X → start with drivers of X
If the question is why is X deteriorating → root-cause tree can make sense

So for “margin pressure due to low-cost entrant,” I’d probably still start:

revenue pressure
cost pressure

And only then go into competition if needed.

Many candidates go external too early.

3. Don’t aim for perfect trees in minute one
Good candidates don’t have a perfect issue tree from the start.

They have:

a clean top layer
a strong logic
then they refine

That’s enough.

4. Best drill I know (very effective)
Take random business prompts and spend 2 minutes only on first-level structure.

No full case.

Just practice:

objective
2–3 top-level drivers
one level below

Do 10 of those and you improve faster than doing 2 full cases.

Also a good exercise:
force yourself to start every structure from one of these:

equation
process
decision split

It trains first-principles thinking.

And one last thought: the fact that you notice when you go “too broad” is already a very good sign. That’s actually the hard part.

If helpful, happy to help you practice this — structuring is very trainable once the logic clicks.