Great Lakes Consulting Club · Practice-first

Think clearly under pressure.

Case interviews rarely fail because someone forgot a framework. They fail when the candidate stops listening, hides an assumption or reaches a recommendation the analysis does not support. This page helps you practise those moments.

Enter the practice lab Explore the preparation path

Want the reasoning behind this approach, written out in full? Read Cracking Consulting Interviews →

Core loop

Scope → Structure → Synthesise

North star

Quality over case count

Worth asking

Define the decision before you reach for a framework.

Are you listening to the case, or running your framework on autopilot?
Which assumption in your structure would break the whole recommendation if it's wrong?
Could the arithmetic be correct while you've misread the business?

01 / Preparation system

Train the process, not the template.

A framework can help you begin, but it cannot listen for you. Clarify the question, build a structure for this particular situation, follow the evidence and say what it means. Then review the attempt while it is still fresh.

01
Stage 01
Learn the interview
Understand what interviewers assess: problem structuring, analytical thinking, synthesis and persuasive communication.
02
Stage 02
Practise the building blocks
Practise issue trees, business arithmetic, chart reading and top-down communication before adding case complexity.
03
Stage 03
Run deliberate cases
Use live mocks, rotate industries and capture precise feedback—not just the number of cases completed.
04
Stage 04
Reflect and repeat
Review patterns in your case log, isolate one improvement area and test it in the next interview simulation.

02 / Interactive practice lab

Rehearse the moments that matter.

Practise structuring, quantitative reasoning and synthesis separately before combining them in a full case. After each mock, turn one piece of feedback into the next session's goal.

Practice mode · Structure

Turn ambiguity into a clean issue tree

Your client is a premium coffee chain. Revenue is growing, but profit has fallen for three consecutive quarters. Where would you begin?

1Confirm the objective, time horizon and geography
2Separate revenue and cost drivers before forming hypotheses
3Start with the branch most likely to explain the decline
4State what data would validate or reject the hypothesis

03 / Complete original practice case

Nadi Kitchens: growth without profit.

This fictional case is written for this site. Work through it with a partner: the candidate should see only the brief at first, while the interviewer opens each exhibit when the analysis earns it.

The arithmetic is intentionally manageable. The harder work is deciding what the numbers mean, naming the assumptions behind a recovery plan and giving a recommendation that can survive a follow-up question.

Candidate brief · Read aloud

The client is growing, but the economics are moving backward.

Nadi Kitchens is a fictional subscription lunch-delivery business. Monthly orders have grown by 20% over the past year, yet monthly operating profit has fallen. The CEO wants to restore last year’s profit within three months without worsening on-time delivery or meal quality. Diagnose the decline and recommend what management should do first.

Clarify

Define profit, time horizon and non-negotiable service constraints.

Structure

Separate price, volume, variable cost, fixed cost and mix.

Decide

Recommend a sequenced plan, not a list of every possible lever.

Exhibit 1 · Monthly economicsReveal

Nadi Kitchens monthly economics last year and currently
Metric	Last year	Current
Orders per month	100,000	120,000
Average revenue per order	₹250	₹240
Food cost	40% of revenue	44% of revenue
Delivery cost per order	₹40	₹50
Fixed cost per month	₹80 lakh	₹84 lakh

Candidate task: calculate operating profit in both periods, quantify the gap and identify which movements deserve investigation first.

Exhibit 2 · Calculation and diagnosisReveal

Last-year profit

₹30 lakh

₹2.5 crore revenue minus food, delivery and fixed cost.

Current profit

₹17.28 lakh

₹2.88 crore revenue minus ₹1.2672 crore food, ₹60 lakh delivery and ₹84 lakh fixed cost.

Profit gap

₹12.72 lakh

The amount the three-month plan must recover each month.

Diagnosis

Unit economics weakened

Volume grew, but lower revenue per order and higher food and delivery cost absorbed the gain.

Exhibit 3 · Management’s three proposed leversReveal

Improve route density

Reduce delivery cost by ₹6 per order without lowering on-time performance.

Illustrative contribution: +₹7.2 lakh per month

Reduce food waste

Bring food cost from 44% to 43% of current revenue while protecting quality.

Illustrative contribution: +₹2.88 lakh per month

Recover value in price and packaging

Improve net revenue by ₹4 per order after any demand response.

Illustrative contribution: +₹4.8 lakh per month

Interviewer guide · What a strong synthesis containsReveal

Nadi should pursue a sequenced recovery plan centred first on delivery route density, because that is the largest proposed lever and directly addresses the sharpest unit-cost deterioration. In parallel, it should run a controlled food- waste intervention and test the ₹4 net revenue recovery on a limited customer segment. Together, the illustrative contributions total ₹14.88 lakh per month, above the ₹12.72 lakh gap, but that is not yet a forecast.

Management should track on-time delivery, complaints, repeat orders, food waste and realised net revenue. If service or retention weakens, the plan must be revised even if the spreadsheet still appears to close.

Probe the candidate

Which assumption is most likely to fail?
How would you test price response before a full rollout?
What implementation cost is missing?
What would make you stop the route-density change?

04 / Case architecture

Recognise the pattern; do not force the template.

These case families can help you find a sensible first question. After that, the facts of the case should determine the structure.

Profitability

What changed in revenue, cost or mix?

Market entry

Is the market attractive, accessible and winnable?

Growth

Where can value expand—and what must be true?

Pricing

What value does the offer create, what will customers pay and how might competitors respond?

M&A / PE

Will the asset create value, and can the deal be completed and integrated?

Abstract

Can you create structure when no familiar template fits?

A disciplined guesstimate

Keep assumptions visible and logic easy to check.

01
Define
Clarify the metric, geography and time period.
02
Decompose
Choose a demand-side or supply-side equation.
03
Estimate
Use explicit assumptions and rounded arithmetic.
04
Sanity-check
Triangulate, interpret and state the sensitivity.

05 / Interview fluency

What the interviewer needs to hear.

Problem framing

Clarify the decision, objective and constraints.

Structured analysis

Break the problem into answerable branches.

Evidence & insight

Calculate, interpret and update the hypothesis.

Executive synthesis

State the recommendation, support it, address the main risk and define the next step.

06 / Industry fluency

Learn value chains, not trivia.

For each sector, know how value is created, what drives revenue and cost, which metrics matter, and where disruption changes the economics.

E-commerce, retail & FMCG
Banking, NBFCs & insurance
Healthcare & pharmaceuticals
Technology, AI & IT services
Automobile, airlines & logistics
Energy, infrastructure & real estate

Great Lakes Consulting Club learning path

Build readiness in five connected layers.

Use this sequence as a curriculum rather than a reading list. Learn how the interview works, practise the building blocks, solve full cases, sharpen estimation and then add the industry context needed to make commercially grounded recommendations.

01
Consulting prep 101
Know the interview process, evaluation criteria and how to use a case group well.
02
Case frameworks
Build adaptable starting structures for common case families and unusual prompts.
Open
03
Case examples
Move from candidate brief to analysis, exhibits, synthesis and interviewer feedback.
Open
04
Guesstimates
Define, decompose, estimate and sanity-check with visible assumptions and units.
Open
05
Industry primers
Learn business models, value chains, economics, KPIs, competition and emerging trends.
Open

A practical cadence is to form a diverse group of four to six people 45–60 days before interviews, run realistic 20–25 minute cases in pairs, keep a feedback log and revisit recurring mistakes every four or five days. Rotate interviewers and industries, and finish with random mocks and back-to-back simulations. The goal is progress, not case count.

Think clearly under pressure.

Want the reasoning behind this approach, written out in full? Read Cracking Consulting Interviews →

Metric

Last year

Current

Orders per month

100,000

120,000

Average revenue per order

₹250

₹240

Food cost

40% of revenue

44% of revenue

Delivery cost per order

₹40

₹50

Fixed cost per month

₹80 lakh

₹84 lakh

Build readiness in five connected layers.

Define the decision before you reach for a framework.

Train the process, not the template.

Learn the interview

Practise the building blocks

Run deliberate cases

Reflect and repeat

Rehearse the moments that matter.

Turn ambiguity into a clean issue tree

Nadi Kitchens: growth without profit.

The client is growing, but the economics are moving backward.

Clarify

Structure

Decide

Improve route density

Reduce food waste

Recover value in price and packaging

Probe the candidate

Recognise the pattern; do not force the template.

Keep assumptions visible and logic easy to check.

Define

Decompose

Estimate

Sanity-check

What the interviewer needs to hear.

Problem framing

Structured analysis

Evidence & insight

Executive synthesis

Learn value chains, not trivia.

Build readiness in five connected layers.

Consulting prep 101

Case frameworks

Case examples

Guesstimates

Industry primers

Define the decision before you reach for a framework.

Train the process, not the template.

Learn the interview

Practise the building blocks

Run deliberate cases

Reflect and repeat

Rehearse the moments that matter.

Turn ambiguity into a clean issue tree

Nadi Kitchens: growth without profit.

The client is growing, but the economics are moving backward.

Clarify

Structure

Decide

Improve route density

Reduce food waste

Recover value in price and packaging

Probe the candidate

Recognise the pattern; do not force the template.

Keep assumptions visible and logic easy to check.

Define

Decompose

Estimate

Sanity-check

What the interviewer needs to hear.

Problem framing

Structured analysis

Evidence & insight

Executive synthesis

Learn value chains, not trivia.

Build readiness in five connected layers.

Consulting prep 101

Case frameworks

Case examples

Guesstimates

Industry primers