In a typical first round of eight candidates, two or three leak points not on math but on format: they wait for a McKinsey prompt that never comes, or they sit still in a BCG case waiting to be led. The firms publish different processes. Treating those differences as trivia to recite is the mistake. Treating them as scheduling constraints is the job.
McKinsey pairs an interviewer-led problem-solving interview with a Personal Experience Interview and, for most consulting roles, Solve. BCG runs a candidate-led live case inside a published four-step process and, depending on office, a Consulting Career Assessment plus an online case. Bain expects you to drive structure in the case and, when assigned, completes a Sova or TestGorilla digital assessment in roughly 30 to 40 minutes. After this page you should be able to put those gates on a calendar and practice the right muscle on the right week.
What the scoring sheet actually rewards
I have scored hundreds of cases. The sheet does not have a box for "knows that McKinsey is interviewer-led." It has boxes for structure, quantitative accuracy, insight from exhibits, synthesis, and whether you are someone the interviewer would put in front of a client.
The format only changes when those skills show up:
| Firm | Published process you must schedule around | Case posture in the room | Fit / behavioral load |
|---|---|---|---|
| McKinsey | Solve for most consulting roles; then PEI + problem-solving interview | Interviewer-led: answer the prompt in front of you | Heavy: PEI themes with depth |
| BCG | Application → skills interview → case → team interview; CCA and/or online case by office | Candidate-led: you choose the path | Woven through, not a separate PEI product |
| Bain | Digital assessment (Sova or TestGorilla) when required; then case rounds | Candidate-led posture in Bain's own prep materials | Fit and composure, usually lighter than McKinsey PEI |
McKinsey states that for most client-facing roles you do a personal experience interview followed by a problem-solving interview. BCG publishes a four-step consulting interview process. Bain publishes that the digital assessment is mandatory when assigned and that applications without it are not considered.
Folklore lives on Reddit: "Bain switched fully to interviewer-led," "every BCG office uses Casey." Firms do not publish a single global case style sheet. Prep for the published posture, then adapt if your interviewer runs tighter or looser.
The constraint map before you open a casebook
Put the non-case gates on paper first. Case reps expand to fill whatever time is left; assessments do not wait for your structure muscle to be ready.
McKinsey Solve. Gamified assessment. McKinsey says no business knowledge or gaming experience is required and that Solve is considered with the rest of the application. Invitation length is in your email. Block a quiet 60 to 90 minutes the week you expect the invite, not the night before a partner coffee.
BCG CCA and online case. For U.S. Associate recruiting, BCG states the Consulting Career Assessment (CCA) invitation arrives 30 to 90 minutes after application, takes about 30 to 35 minutes, and you have 48 hours to finish it. A select group is invited to an online case of about 35 minutes roughly two weeks after the deadline. That 48-hour CCA window is the constraint most candidates underestimate.
Bain Sova or TestGorilla. Bain's digital assessment page says you learn which vendor you get by email, the assessment takes approximately 30 to 40 minutes, TestGorilla is one sitting, Sova need not be one sitting but all sections must finish by the deadline, and AI assistance is prohibited.
If you are applying to all three in one season, you can easily lose three separate half-days to screens before a single live case. Plan those half-days. Do not "squeeze in" a full mock the same evening as CCA.
Eight weeks, built around the gates
Assume you have eight weeks before your first live interview, and you might face more than one firm. Adjust the start week if your first invite is sooner; compress weeks 1 to 3, do not skip the assessment blocks.
Weeks 1–2: Shared case muscle only
Goal: one clean profitability or market-entry structure, one exhibit conclusion stated in a sentence, one math setup with units, one recommendation with a risk and a next step. No firm costume yet.
Daily: 20 minutes of math or charts. Three times a week: a 25-minute structure-only prompt. Twice a week: a full timed case, solo or with a partner.
Stop condition before you leave this block: you can open a case without asking "what framework should I use," and your synthesis names a decision, not a summary.
Week 3: Assessment week
Treat this as a product week, not a case week.
| Day | Block | Why |
|---|---|---|
| Mon | Bain-style numerical / SJT practice if Bain is live; else pure quantitative drills | Sova/TestGorilla sit on numerical and judgment skills Bain already named |
| Tue | BCG CCA window rehearsal: 35 quiet minutes, no notes coaching | You may get only 48 hours when the real invite hits |
| Wed | McKinsey Solve familiarity pass if McKinsey is live; otherwise rest | Solve tutorials are untimed; panic is the failure mode |
| Thu | One full general case | Prevent skill decay |
| Fri | BCG online-case style: timed chatbot case + 60-second video recommendation | Casey / OCE is exhibit-heavy and paced by the bot |
Use CoachNed's BCG Casey-style CopperCup case, the CCA numericals tool, Bain Sova practice, and the McKinsey Solve-adjacent simulators (Sea Wolf, Red Rock, SFL) as dress rehearsals for your invite, not as substitutes for the firm's own materials.
Weeks 4–5: Firm rotation, not firm theater
Three full cases per week, one in each posture, plus PEI on McKinsey days.
McKinsey day. Interviewer-led: partner feeds one question at a time. After the case, one PEI story for 12 to 15 minutes with follow-ups. McKinsey asks you to prepare detailed examples across its published PEI themes; depth beats breadth. Two stories per theme is the firm's own suggestion on the interviewing page.
BCG day. Candidate-led: you decide the next branch, ask for data, and own silence. No partner prompts unless you are stuck for two minutes. End with a CEO-ready recommendation in under 60 seconds (same muscle as the online-case video).
Bain day. Candidate-led with Bain's published habits: clarify the objective, walk the structure aloud, share calculations even when unsure, watch cues, highlight the numbers that matter. Bain's own case interview page lists those behaviors explicitly.
Score every case on the same five lines (structure, math, exhibits, synthesis, coachability) so firm days remain comparable. If McKinsey days score fine and BCG days collapse, the issue is drive, not "BCG frameworks."
Week 6: Worked example — allocate 14 practice hours
Suppose you have 14 hours this week and invites from all three firms in the next month. A common bad allocation: 12 hours of generic cases, 2 hours of "reading about firms."
A better split you can reproduce:
- 4 hours candidate-led full cases (BCG/Bain posture): open, structure, request data, prioritize, synthesize.
- 3 hours interviewer-led cases: answer the prompt on the table; do not invent a detour.
- 3 hours PEI: one story per session, then hostile follow-ups ("What would you do differently," "Who disagreed").
- 2 hours assessment dress rehearsals: one CCA-length block, one chatbot case, or one Sova-style numerical set.
- 2 hours math and charts only: no full narrative.
That is 14 hours. Notice PEI and assessments get five hours combined. Candidates who "only practice cases" are the ones who fail McKinsey on PEI or BCG on a 48-hour CCA they treated as optional.
Week 7: Back-to-back simulation
Two days that look like interview days: morning case + fit, afternoon case + fit. For McKinsey simulation, PEI first then case, matching the published order. For BCG/Bain, fit woven around the case. Record one recommendation video under a minute.
Week 8: Firm of record only
Whichever firm interviews first gets 70 percent of the reps in its posture. Keep one general case so you do not overfit. Protect sleep the night before Solve, CCA, or Sova; those are not days for a heroic third mock.
Ned's rule. Put every published assessment on the calendar the day you submit the application. Case volume after the invite is vanity; unfinished CCA or Sova is a hard stop.
A scoring heuristic for "am I ready to firm-specialize"
Use this before you abandon general prep. I score a candidate ready to specialize when, across three recent timed cases, they hit all of:
- Structure: custom MECE tree in under three minutes, with an explicit "I would test X first because…"
- Math: setup stated with units; arithmetic error rate under one per case
- Exhibits: insight before calculation ("share shifted 4 points to private label" before the CAGR)
- Synthesis: decision + evidence + risk + next step in under 90 seconds
- Coachability: visible use of a hint within one sentence of receiving it
Until that bar holds, McKinsey PEI polish and BCG "drive" drills are theater. Firm differences amplify a solid base; they do not create one.
Practice this week
Run one interviewer-led case and one candidate-led case back to back, then one PEI story with at least four follow-ups. If you want a timed first rep without an account, use /start. For an 18-minute live voice case with a seven-score debrief, use /interview. Everything on CoachNed is open for seven days with no card; then $120 for a recruiting season or $49 a month.
Frequently asked questions
How do McKinsey, BCG, and Bain case interviews differ?
McKinsey's published interview for most client-facing roles is a Personal Experience Interview plus an interviewer-led problem-solving interview, often after Solve. BCG's published process is application, skills interview, case, and team interview, with candidate-led live cases and office-dependent CCA / online case screens. Bain assigns Sova or TestGorilla when required and expects you to clarify, structure aloud, and drive analysis in the case.
How many weeks do I need for MBB case interview prep?
Eight weeks at roughly five to seven focused hours per week is enough for most candidates who already have quantitative comfort. Compress to four weeks only if the shared skill bar already holds; otherwise you will arrive at PEI or Casey undercooked.
Should I practice McKinsey, BCG, and Bain cases separately?
Rotate postures after the shared base is stable: interviewer-led plus PEI for McKinsey days, candidate-led drive for BCG and Bain days, plus dedicated assessment dress rehearsals. Separate branding without separate postures wastes time.
What is the BCG Consulting Career Assessment?
BCG describes the CCA as a multidimensional assessment that looks beyond the resume. For U.S. Associate recruiting as of 2026, invitations typically arrive shortly after application, take about 30 to 35 minutes, and allow 48 hours to complete. It is separate from the online case some candidates also receive.
How long is the Bain digital assessment?
Bain states approximately 30 to 40 minutes. You are told whether you will take Sova or TestGorilla in the invitation email. TestGorilla is one sitting; Sova may be split, but all sections must finish by the deadline.
Sources
- Interviewing at McKinsey — PEI plus problem-solving interview; Solve mentioned for consulting roles. Checked 2026-09-24.
- Solve, McKinsey's assessment game — official Solve description and integrity rules. Checked 2026-09-24.
- BCG consulting interview process — four published steps for consulting interviews. Checked 2026-09-24.
- BCG United States Associate opportunities — CCA timing (30–90 minutes after apply, ~30–35 minutes, 48-hour window) and online case (~35 minutes). Checked 2026-09-24.
- Bain digital assessment — Sova vs TestGorilla, 30–40 minute duration, mandatory when assigned. Checked 2026-09-24.
- Bain case interview preparation — published case habits (clarify, structure aloud, think aloud, adapt to cues). Checked 2026-09-24.
CoachNed is not affiliated with McKinsey, BCG, Bain, or any firm named in this article.