"Fit" in a case interview is the 10–15 minutes of why you / why consulting / why this firm, plus the questions that land mid-case ("how would you tell the CFO?", "who on the client will hate this?"). It is not McKinsey PEI. PEI is one past story, 10–20 minutes, no switch (PEI guide, PEI questions). Mixing the two is how people give a 90-second why-McKinsey and then have nothing under the first PEI probe.
This page is the motivation and in-case fit layer. Cross-firm story craft: behavioral interview consulting. Why consulting as a full argument: why consulting. BCG's version of the 3 Whys: BCG fit.
Last full pass: 24 August 2026. CoachNed is independent practice material, not affiliated with MBB or boutique firms.
Question types and the shape of a pass
| Type | Signal | Time box | Pass | Fail |
|---|---|---|---|---|
| Walk me through your resume | Thread, not CV karaoke | 60–120 sec | Two turns, then why this room now | Chronology with no point |
| Why consulting | Real trade-off vs banking / industry / startup | 60–90 sec | Three reasons you can defend | "I like problems and people" |
| Why this firm | Substitution test | 45–75 sec | Office, practice, or conversation that dies if you swap logos | "Best training, smartest people" |
| Why this office | Staffing, language, life | 30–45 sec | A constraint you actually have | "World-class city" |
| Mid-case people probe | Client EQ | 20–40 sec | Named resistance + what you'd do Monday | "I'd communicate more" |
| Questions for them | Curiosity | 2–3 good ones | Their work, not Glassdoor | "What's the culture like?" |
McKinsey still runs PEI and these. Do not spend PEI proving why consulting. Do not spend why-consulting telling a Leadership story.
Worked example: "Why Dallas / why not New York?"
Weak. "Dallas is growing and I love Texas. The office has great people. I'm happy to travel."
Strong (45 seconds). "I will be in Dallas regardless — partner is in residency at UT Southwestern for three years, and I already have family housing there. Bain's local staffing model means the case mix I saw in coffee chats (health systems, PE diligence on Texas industrials) is the work I would actually do, not a New York financial-services default. If I were location-flexible I would still rank Dallas first for that mix; I'm not going to pretend a New York offer is equivalent. The risk I already accepted is less PE brand-name on the street; the trade is the work and the life."
What to copy. A constraint that is true, a firm-specific staffing fact (Bain local staffing is a real differentiator described on what is Bain and the Bain cover letter page), a trade-off you name before they do. If you are applying to McKinsey Dallas, swap in a conversation with a Dallas EM, not Bain's staffing model.
If you do not have a geographic constraint, say what you asked about staffing and industry mix, not cuisine.
Resume walk-through: one thread
Do not read the page. Three beats: (1) where you started, (2) two moments that built the skill this job uses, (3) why this interview. End forward.
Example thread: "Ops analyst → I learned to kill a metric that looked good in HQ → MBA to get the client-facing version of that fight → I want your ops practice, not a general 'strategy' cloud."
Then they will pick a PEI/fit story from the same resume. The walk-through should not consume the story.
Mid-case fit probes (the ones that surprise people)
These are not PEI. Short.
- "The CFO hates this recommendation. What do you do?" Name her incentive (earnings this quarter), offer a staged test, do not abandon the number.
- "Your teammate wants to show all 14 slides." You cut to the one exhibit that changes the decision; you tell them why before the partner meeting.
- "What would you want to know from the plant manager?" A constraint you cannot see in the Excel.
Practise keeping EQ while you still case: try. Structure under interruption: drills.
Failure modes for "fit questions" searchers
- Memorizing 30 PEI prompts for a why-office question. Wrong tool.
- A why-firm that passes the name-swap. Rewrite.
- Two minutes of autobiography for "tell me about yourself."
- No questions. You wasted the last five minutes.
- Lying about geography. Offer-matching will expose it.
- Using CoachNed as a credential. Ned built the product in leftover hours. Name-dropping him is not a substitute for your own stories, and it is not a Deloitte endorsement.
A 10-item rehearsal list (not 30 PEI questions)
Practise these out loud. Keep each under the time box above.
- Walk me through your resume.
- Why consulting — and why not stay in your industry.
- Why this firm.
- Why this office.
- Why this practice / why generalist.
- Tell me about a time you disagreed (90-sec version; full PEI elsewhere).
- What feedback have you heard twice.
- What questions do you have for me.
- (Mid-case) How would you sequence this with a skeptical client.
- (Mid-case) Who gets hurt by your recommendation.
For McKinsey depth on item 6, leave this page and use PEI. For BCG's looser 3 Whys, BCG fit. For the motivation essay behind item 2, why consulting.