Most candidates prep fit as if each firm runs a different sport: McKinsey PEI scripts, BCG "why" lists, Bain experience answers, then a separate STAR deck for Deloitte or PwC. That is the wrong map. The labels and airtime change. The scoring muscle does not.
What actually separates offers from polite declines is whether one real decision — yours — survives five to ten minutes of probing. After this page you will have a firm-by-firm format table anchored to careers pages, the five dimensions that keep recurring under those labels, a worked probe-and-score example, and a story-bank method you can reuse across MBB and the Big Four.
This is the cross-firm guide. Firm-specific depth lives on the PEI, BCG fit, and STAR pages linked at the end. CoachNed's PEI and behavioral simulator is at /behavioral.
What each firm publishes (not what forums invent)
Firms publish less than prep folklore claims. Use their own words for format; treat Reddit and Glassdoor as where rumors live, not as scoring sheets.
| Firm | What their careers pages call it | What they say they assess | Depth pattern (as published or strongly implied) |
|---|---|---|---|
| McKinsey | Personal Experience Interview (PEI), then a problem-solving interview | Experiences in detail; your specific role and the actions that drove change; prepare two examples for each of four themes | One story, deep probes; do not hop to a second anecdote mid-dimension |
| BCG | Skills Interview (experience, skills, motivation); behavioral portion also appears in live rounds | Curiosity, collaboration, values plus "core competencies"; go beyond the resume | Shorter, conversational; often paired with a case rather than a standalone PEI hour |
| Bain | Behavioural interview for some roles; behavioural questions may sit inside other interviews | Intellectual curiosity, entrepreneurial drive, results for clients/stakeholders; same scripted questions per role to reduce bias; why Bain specifically | Role-dependent: standalone behavioural for some paths; consulting routes emphasize digital assessment then cases |
| Deloitte | Behavioral interview (STAR explicitly recommended) | Achievement track record, communication, leadership and teaming, aptitude; priorities, initiative, conflict, ambiguity | More prompts, less single-story depth than McKinsey; empty Action still fails |
| PwC | Behavioural / competency interviews against the PwC Professional | Trusted Leadership and Distinctive Outcomes (impact on others, coaching, growth; quality/integrity, business mindset, collaborative delivery) | Map stories to the two dimensions before interview day |
| EY | What we look for (mindsets and behaviours) | Innovate, think analytically, act globally; strong communicators, team players, adaptable leaders | Competency-style examples; intercultural teamwork called out explicitly |
| KPMG | Motivational and behavioural interviews (e.g. Australia graduate FAQs); local "Everyone a Leader" language varies by market | Resilience, curiosity, progressive thinking, collaboration; STAR often suggested for structure | Similar to other Big Four: several scored prompts, not one 20-minute PEI |
Office and role still override any table. Your recruiter email wins. What does not change is the interviewer listening for ownership you can defend under follow-up.
Some McKinsey regional pages still list older labels (personal impact, entrepreneurial drive, inclusive leadership) alongside problem solving. The global interviewing page asks for two examples across four PEI themes and stresses detailed actions. Prepare depth either way; do not argue taxonomy with your interviewer.
The five dimensions that recur under every label
Strip the brand names and the same five signals show up on every sheet I have used or trained against. McKinsey's PEI themes, BCG's curiosity and collaboration language, Bain's entrepreneurial and results language, Deloitte's leadership and teaming prompts, and PwC's Trusted Leadership / Distinctive Outcomes all collapse onto this set:
| Dimension | What the interviewer is listening for | Counterfeit that dies on probe two |
|---|---|---|
| Ownership | A choice you made that others did not | "I was part of the team that…" |
| Influence | A named person who wanted something else, and how you moved them | "Stakeholders were aligned" |
| Judgment under friction | Trade-offs, incomplete data, a real cost | Hero weekend with no downside |
| Results | Checkable change: time, money, quality, a reversed decision | "It went well" |
| Reflection | What you would change; what you were wrong about | "Nothing — it was perfect" |
STAR (Situation, Task, Action, Result) is a spine Deloitte and others still teach publicly. It fails when Action is a slogan and Results have no number. PARADE-style add-ons (rationale, lesson) help if they force reflection. Use whatever acronym you like. Fill Action and Result.
Airtime rule from the room: Situation is one breath. Action is most of the minutes.
How probing works (and why scripts crack)
The first answer is rarely the score. The score lands on whether your story still has oxygen after the interviewer asks for the other person's view, the Tuesday that went wrong, and the decision you alone made.
Worked example: one story, three probe layers
Facts (invented; use your own). You led a four-person campus consulting club project for a local grocer. The client wanted a "loyalty app" recommendation in three weeks. Your analysis showed 62% of margin came from 18% of SKUs; an app would cost roughly $40k year one against maybe $12k of attributable lift. A teammate wanted to deliver the app roadmap the client asked for. You wanted a SKU-focus pilot instead.
Layer 0 opener (~60–90 seconds). Name the dissent, your action, one number, one miss.
"The client asked for a loyalty-app plan. Our margin cut showed 62% of profit in 18% of SKUs, so an app looked like a $40k cost against about $12k of lift. I told the teammate who owned the app slides we should not recommend it. I rebuilt the deck around a four-week SKU pilot, called the store manager with the teammate on the line, and we left with a yes on the pilot. I mishandled the first confrontation — I emailed the client before aligning the team — and I would never do that again."
Layer 1 probes (what BCG/Bain/Big Four often stop at). Who disagreed? What did only you do? What changed?
Layer 2 probes (McKinsey PEI depth). Exact words in the disagreement. Sequence of meetings. What the teammate said about you afterward. What you still think you got wrong. What you would do in week one next time.
| Probe | Weak reply (score leak) | Strong reply (scoreable) |
|---|---|---|
| "What did your teammate want?" | "They wanted to help the client." | "They wanted the app roadmap because the brief named it and they had already drafted six slides." |
| "What did you do that others did not?" | "I coordinated the team." | "I rebuilt the recommendation overnight, booked the manager call, and owned the trade-off: we would miss the original brief and risk a no." |
| "What would you change?" | "Nothing major." | "I emailed the client first. That blindsided my teammate. Next time I settle the internal fight before any client touchpoint." |
Reproduce the scoring heuristic: give yourself one point for a named dissenter, one for a first-person action others did not take, one for a checkable result, one for a concrete miss. A four is interview-ready. A two is a slogan with a resume bullet glued on.
Ned's rule. If your story has no other person who wanted something else, it is not a leadership or influence story — it is a diary entry. Rewrite until someone can disagree with you on the record.
Build a story bank, not thirty speeches
McKinsey's interviewing page suggests two personal examples per assessed area. That is the right density for every firm: a thin bank of deep stories beats a thick binder of 90-second blurbs.
| Slot (one-line cue) | Primary dimension | Secondary | Do not use for |
|---|---|---|---|
| Changed a plan when data killed the brief | Judgment | Ownership | Pure "why consulting" |
| Moved someone without formal authority | Influence | Conflict | Teamwork fluff with no friction |
| Led without the title | Ownership | Ambiguity | Slide-making as heroism |
| Failed, then changed the system | Reflection | Growth | Blame theater |
| Delivered under an ugly constraint | Drive / results | Resilience | Hero weekend with no cost |
| Values tension with a real temptation | Judgment | Integrity | Fake ethics with no risk |
Two examples per muscle if you can. If every row is the same internship, the bank is too thin: one bad probe collapses the whole round.
Compression test: for BCG, Bain, or Deloitte, open in 90 seconds. For McKinsey PEI, keep the same spine and stock five more minutes of detail. Do not invent a second story mid-PEI; interviewers hear the abandon.
Practice this until probes stop surprising you
Today. Write twelve one-line cues. Kill anything that starts with "I worked hard."
Tomorrow. Turn six into 90-second openers. Time them. Count the word "we."
Day three. Pick your weakest story. Answer out loud: what did others want? What did only you do? What would you change?
Day four. One McKinsey-depth run on that story — four follow-ups minimum. Record it.
Then put the same story under live follow-ups in CoachNed's behavioral simulator at /behavioral (four follow-ups, scored like a PEI). Everything is open for seven days, no card; then $120 for a recruiting season or $49 a month.
Case still matters. Fit does not replace it. If you need a first case rep the same week, use /start.
Frequently asked questions
Is the consulting behavioral interview the same as McKinsey PEI?
No. PEI is McKinsey's deep personal-experience format — often one dimension, many probes. BCG, Bain, and Big Four firms usually ask more prompts with less single-story depth, though Bain may run a dedicated behavioural interview depending on role. Prepare PEI-deep and you have leftover for shorter formats.
How many stories do I need for consulting fit interviews?
A working bank is six to eight deep stories that map to ownership, influence, judgment, results, and reflection — not thirty prompt-specific speeches. McKinsey publicly suggests two examples per PEI theme; that density travels well to BCG, Bain, and competency frameworks at PwC and peers.
Should I use STAR for McKinsey PEI?
STAR is fine as a spine. McKinsey's own guidance emphasizes your specific role, challenges, and the actions that drove change, at conversational length. The failure mode is a tidy STAR with no oxygen for probes — not the acronym itself.
Do Big Four consulting interviews care about fit as much as MBB?
Yes, differently packaged. Deloitte publishes behavioral tips and STAR. PwC recruits against the PwC Professional dimensions. EY and KPMG publish mindset and behavioural language. Expect more prompts and clearer competency labels; do not expect lighter standards on ownership and results.
What if my interviewer asks "Why consulting?" in a behavioral slot?
Treat motivation as a separate muscle from leadership and influence stories. Keep a tight why answer ready, but do not smuggle it into a conflict or leadership prompt. See the dedicated why-consulting guide in the related links.
Sources
- Interviewing at McKinsey — PEI format, two examples per four themes, focus on specific role and key actions. Checked 2026-09-24.
- BCG consulting interview process — Skills Interview (experience, skills, motivation); values and core competencies; behavioral portion noted by interviewers. Checked 2026-09-24.
- Bain interviewing — Behavioural interviews for some roles; curiosity and entrepreneurial language; same questions per role; why Bain. Checked 2026-09-24.
- Deloitte behavioral interview tips — STAR structure; achievement, communication, leadership and teaming; sample prompts on priorities, initiative, conflict, ambiguity. Checked 2026-09-24.
- The PwC Professional — Trusted Leadership and Distinctive Outcomes as hiring and development dimensions. Checked 2026-09-24.
- EY — What we look for — Innovate, analytical, and global mindsets; communication, teamwork, adaptable leadership. Checked 2026-09-24.
- KPMG Australia graduate FAQs — Motivational and behavioural questions; STAR suggested for structure. Checked 2026-09-24.
CoachNed is independent practice material and is not affiliated with McKinsey, BCG, Bain, Deloitte, PwC, EY, KPMG, or any firm named above.