Arthur D. Little Case Interview: Format, Sample Cases, and a 2026 Prep Plan

Arthur D. Little case interviews are mostly candidate-led: you build the structure and drive toward a recommendation rather than waiting to be steered through each step. The ADL-specific differences from McKinsey, BCG, and Bain are more frequent market sizing, occasional brainteasers, and a written or presentation case in some offices. Founded in 1886 by MIT chemist Arthur Dehon Little, ADL is strongest in telecom, energy, automotive, chemicals, and healthcare. This guide covers the rounds, the formats, a fully worked numeric example, and a focused prep plan.

About Arthur D. Little

Arthur D. Little is one of the oldest management consulting firms in the world. It was founded in 1886 in Boston by MIT chemist Arthur Dehon Little, formally incorporated in 1909, and pioneered the idea of linking business strategy with technology and R&D. That legacy shows up in milestones like operations research, SABRE, NASDAQ, synthetic penicillin, and LexisNexis, and it shapes the kinds of problems ADL works on today. After a 2002 Chapter 11 filing, the brand passed through Altran, returned to partner ownership in a December 2011 management buyout, and re-established its U.S. presence in 2016.

Current firm profile:

• Headquarters: Brussels, Belgium
• Scale: roughly 1,500 staff across about 46 offices in Europe, Asia, the Middle East, and the United States
• Positioning: Strategy, Innovation, and Transformation
• Primary industries: Telecom/Media/Electronics, Energy and Utilities, Automotive and Manufacturing, Chemicals, Healthcare and Life Sciences, plus Financial Services and Public Services

ADL is not a bulge-bracket generalist. It competes on deep sector expertise and innovation strategy, which makes industry knowledge more useful in ADL interviews than at MBB.

What is the Arthur D. Little interview process?

ADL's process is less standardized globally than MBB's and varies by office and region, but the common shape is about 2 rounds with 4-5 cases in total. A case appears in every round.

Round 0 (initial screen): a phone or in-person conversation, often around an hour. A short background walk-through, then one market sizing question that frequently develops into a fuller case. It is not always labeled a formal interview, but it filters for baseline analytical capability and communication.

Round 1 (1-2 cases): typically run by consultants or junior managers. About 10 minutes of fit (background, motivation, why ADL), then a 30-45 minute candidate-led case, often on market sizing, market entry, revenue growth, or operational efficiency.

Round 2 (1-2 cases plus behavioral): run by senior interviewers and more complex. More open-ended strategy problems, a written or presentation case in some offices, behavioral questioning on leadership and why ADL, and questions tied to ADL's industry practices. Cases are often drawn from the interviewers' own sector backgrounds, so the Round 2 case frequently mirrors the practice area of the person across the table.

Are Arthur D. Little cases candidate-led or interviewer-led?

This is the most commonly misunderstood point about ADL, so it is worth getting right.

Coaches who prepare ADL candidates describe the cases as mainly candidate-led. You build the structure, choose where to dig, and drive toward a recommendation; the interviewer supplies data and asks follow-ups but does not walk you through a fixed sequence the way a McKinsey interviewer does. In that sense ADL sits closer to BCG and Bain than to McKinsey.

Format still varies by office and interviewer, and some candidates report a more guided experience. The safe stance is to lead confidently while staying responsive: if an interviewer redirects you ("let's look at the cost side first"), follow the lead, add depth there, and return to your structure naturally rather than fighting for control.

What case types does Arthur D. Little use?

Common ADL case types include market sizing, market entry and expansion, profitability and cost reduction, M&A, digital and innovation strategy, and operational efficiency. Cases usually run 30 to 45 minutes for the traditional format.

Sample prompts in the style ADL candidates report, mapped to the firm's sector focus:

• "A renewable energy company wants to expand into Southeast Asia. How should they approach it?" (energy, market entry)
• "A telecom provider's margins are declining. Where should they focus?" (telecom, profitability)
• "A healthcare firm is evaluating a biotech acquisition. What are the risks and benefits?" (healthcare, M&A)

ADL cases tend to be grounded in operations, profitability, and go-to-market decisions rather than abstract puzzles, so command of the profitability framework and market entry framework carries you a long way.

A worked Arthur D. Little case with the actual math

Because ADL weights market sizing more than MBB, here is a full worked example with the arithmetic shown, the kind of estimation that often opens an ADL energy or telecom case.

Prompt: "A utility is planning EV charging infrastructure for a mid-sized European country of about 20 million people. Roughly how many public fast-charging stations will the market need in 10 years?"

Step 1: Estimate the EV fleet in 10 years.

• 20 million people, roughly 2 people per household gives about 10 million households.
• Assume about 1 car per household, so about 10 million cars on the road.
• Assume EVs reach about 40% of the fleet in 10 years (policy-driven, plausible for Europe). That is 10 million times 0.40 = 4 million EVs.

Step 2: Decide how many EVs rely on public fast charging.

• Many EV owners charge at home. Assume about 60% have home charging and primarily use it, leaving about 40% reliant on public charging.
• 4 million times 0.40 = 1.6 million EVs dependent on public charging.

Step 3: Size the daily fast-charging demand.

• Assume each dependent EV needs a meaningful public charge roughly twice a week, so about 1.6 million times 2 = 3.2 million charging sessions per week.
• Per day that is 3.2 million / 7, which is about 457,000 sessions per day.

Step 4: Convert demand into number of charging stations.

• A fast charger takes about 30 minutes per session, so one charging point can serve about 2 sessions per hour.
• Assume effective utilization of about 10 hours per day per point (demand is not flat across 24 hours). That is 2 times 10 = 20 sessions per point per day.
• Stations needed = 457,000 / 20, which is about 22,850 charging points.
• If each physical station hosts about 4 charging points, that is 22,850 / 4, or roughly 5,700 fast-charging stations.

Sanity check and synthesis: "So the market needs on the order of 5,000 to 6,000 public fast-charging stations in 10 years, driven mostly by the 1.6 million home-charging-dependent EVs. The answer is most sensitive to two assumptions: EV adoption rate and the share relying on public charging. If home-charging access is higher than 60%, the count drops sharply, so I would validate that first before sizing the client's build-out and capital plan."

That final move, naming the two assumptions that swing the answer most, is what separates a strong ADL market-sizing answer from one that just produces a number. For more reps, work through the market sizing step-by-step guide.

What does ADL's industry focus mean for case themes by office?

ADL is not a generalist across all regions. Each office has practice strengths that show up in case content, and because cases often come from the interviewer's background, the office you target matters.

A Dubai candidate should expect energy and government transformation cases; a Frankfurt candidate should expect automotive and chemicals. Confirm the current practice mix from the office's recent thought leadership rather than assuming every office is the same.

What is the ADL written or presentation case?

Some ADL offices include a written or presentation case, more often in the final round or for senior hires. You receive a problem statement plus detailed data, then produce a recommendation. Reported prep time is about 1 hour if the data is shared on-site, up to 48 hours if shared offline. Either way you build a short deck or written output, present it, and field questions. The skill tested is structured communication under a time constraint, not just analysis. Practice it deliberately with the written case interview guide: read the packet fast, decide your answer early, and spend the rest on evidence and slide logic rather than re-reading.

How should you prepare for Arthur D. Little?

The single biggest shift from generic MBB prep is the practice mix. Because ADL is mostly candidate-led, the test is whether your framework actually drives the analysis, not just whether it is MECE, so weight your reps toward driving a case end to end and judging the close against the case interview scoring rubric. On top of standard framework and math work, give roughly 10% of your time to market sizing (often the opener) and about 5% to brainteasers (largely gone elsewhere, still occasional here, where the goal is composure). Then build real depth in 2 of ADL's focus sectors and read your target office's recent thought leadership, since cases track the interviewer's background. The checklist below turns this into concrete actions.

For foundations, start with the case interview frameworks complete guide, then the case interview synthesis guide for the close you control in a candidate-led case. The case interview types guide helps you recognize which framework a prompt calls for, and case interview examples gives more full walk-throughs. For European boutique peers whose prep transfers well, see the Oliver Wyman, Roland Berger, and PA Consulting guides. To benchmark ADL's candidate-led style, compare the McKinsey (interviewer-led) and BCG (candidate-led) guides. Coming from another field, the case prep guide for career changers maps the transferable skills.

Checklist

Execution checklist

• Drill candidate-led cases where you build the structure and drive it

  ADL cases are mostly candidate-led, so the test is whether your framework actually drives the analysis, not just whether it is MECE

• Allocate roughly 10% of practice time to market sizing

  ADL uses market sizing more often than MBB and frequently opens with it

• Spend about 5% of practice on brainteasers

  Brainteasers are largely gone elsewhere but still appear occasionally at ADL; the goal is composure

• Research ADL's thought leadership in your target industry

  Cases often come from the interviewer's sector background and reflect ADL's published viewpoints

• Identify your target office and prepare for its regional focus

  A Dubai energy interview and a Frankfurt automotive interview have very different thematic content

• Practice the written or presentation case if your office uses it

  Some ADL processes give 1 hour on-site or up to 48 hours offline to build and present a recommendation

• Prepare 5 tight behavioral stories and a specific why-ADL narrative

  ADL screens for independent thinking, creativity, and multi-disciplinary teamwork, and expects a credible reason you chose ADL

Sources (checked June 18, 2026)

• Case Interview, Arthur D. Little official careers page
• Arthur D. Little on Wikipedia
• Arthur D. Little Case Interview Complete Guide, Hacking the Case Interview
• The Arthur D. Little Case Interview, My Consulting Offer
• Arthur D. Little Case Interview: Format, Tips, and Examples, CaseBasix
• Arthur D. Little Interview, UK, PrepLounge consulting forum
• Arthur D. Little Consulting Firm Profile, Management Consulted
• Arthur D. Little Interview Experience, Glassdoor