The three MBB assessments at a glance
Three firms, three different philosophies of pre-interview screening. Don't assume prep for one is prep for all three — the format-specific muscles barely overlap.
McKinsey
Solve (PSG / Digital Assessment)
Sea Wolf (Ecosystem), Red Rock (case study), Sustainable Future Lab (situational judgment). The most simulation-style of the three MBB assessments.
BCG
Casey (Chatbot Case)
A chatbot walks you through a written case interview. You type structured responses to prompts under time pressure — closer to a real case interview than a game.
Bain
SOVA / Online Assessment
Blends numerical and verbal aptitude with situational judgment scenarios. Closer to a classic graduate online assessment than to game-based or case-based formats.
Side-by-side comparison
| Firm | Test | Duration | Format | Measures | Practice availability |
|---|---|---|---|---|---|
| McKinsey | Solve | ~70 min | 3 game-based mini-games | Pattern recognition, structured problem-solving, judgment | Realistic simulators available (SolvePrep, others) |
| BCG | Casey | ~25–35 min | Chatbot written case | Structuring, written communication, math under time | Limited — case-interview prep transfers partially |
| Bain | SOVA / OA | ~45–60 min | Aptitude + situational judgment | Numerical/verbal aptitude, judgment, work styles | Generic SHL/SOVA-style aptitude prep transfers well |
Format differences drive almost all the prep difference. The skills section below is what actually transfers across all three.
McKinsey Solve — what to know
Three mini-games inside roughly 70 minutes, played in a single proctored browser session. Sea Wolf (Ecosystem) is the pattern-heavy trait-matching game; Red Rock is a case-style exhibit investigation; Sustainable Future Lab is situational judgment scored across four pillars. Each game contributes roughly a third of total score. The format has changed names twice (Imbellus → PSG → Solve) but the underlying assessment is what it has been since 2024.
Solve is the most simulation-like of the three MBB assessments, which makes it the only one where realistic browser-based practice meaningfully moves scores. SolvePrep is built specifically for this format.
BCG Casey — what to know
Casey is a chatbot that walks you through a written case interview. The bot poses prompts — structure the problem, do quick math, interpret an exhibit, conclude — and you type responses under time pressure. Total session is roughly 25–35 minutes depending on the variant, with shorter, sharper turns than McKinsey Solve. The scoring is opaque, but the best signal is the quality and clarity of your written structuring, plus speed on the math.
The honest disclosure: SolvePrep does not build a Casey simulator. Standard written-case prep (frameworks, structured opening, MECE breakdowns) transfers partially. Practising typed responses to case prompts under a timer is the closest free analog — there's no clean game-based simulator equivalent.
Official source: BCG Casey on the BCG careers site.
Bain SOVA — what to know
Bain's online assessment in most regions is a SOVA-style test (built on the SOVA Assessment platform): numerical reasoning, verbal reasoning, situational judgment, and work-style preference sections, typically 45–60 minutes total. It's the closest of the three to a classic graduate aptitude assessment — closer to what you'd see at a bank or Big 4 firm than to McKinsey's game-based format.
The honest disclosure: SolvePrep does not build a SOVA simulator. Generic SHL/SOVA-style aptitude practice (numerical, verbal, situational judgment drills) transfers directly. Plenty of free and paid aptitude-prep platforms cover this well — far better than any MBB-specific tool.
Bain doesn't publish a single canonical page for the assessment; Bain careers and your office recruiter are the source of truth for whether you'll get SOVA, a Pymetrics variant, or a case-only screen.
What prep actually transfers across all three
Four underlying skills earn marks at McKinsey, BCG, AND Bain. If you have only days to prep and you're applying to multiple firms, drill these rather than format-specific content:
Structured problem-solving
MECE breakdowns, hypothesis-driven reasoning, clean issue trees. Earns marks in Red Rock, Casey structuring prompts, and SOVA situational judgment alike.
Exhibit and data reading speed
Quickly extracting the right number from a busy chart or table. Critical in Red Rock, in Casey math prompts, and in the SOVA numerical section.
Judgment under ambiguity
Picking the least-bad answer when no option is obviously right. Sustainable Future Lab and SOVA situational judgment both reward this directly; Casey rewards it implicitly through scoring on response quality.
Typed output under a timer
All three assessments are typed. Casey is the most writing-heavy; SOVA and Solve still penalise slow input. Practise drafting clean, structured short answers in under 2 minutes.
If you only have time to prep for one
Most candidates can't afford to prep equally for three different assessments. Pick by your actual situation, not by which firm sounds most prestigious:
You already have a McKinsey invite
Prep Solve first. It's the longest test with the highest format-specific gotcha density and the only one where realistic simulator practice meaningfully moves your score. Use the 7-day prep plan.
You have a BCG invite only
Drill written case structuring with a timer. Mock case interviews (with a partner or using free chat-based case generators) build the typed-response muscle Casey rewards. Generic MBB case prep transfers — Solve-specific simulator practice does not.
You have a Bain invite only
Standard graduate aptitude prep (SHL/SOVA-style) is the highest-leverage option. There are many strong free and paid aptitude platforms. MBB-specific prep tools, including SolvePrep, won't move your SOVA score.
You're applying to all three
Start with the four transferable skills above. Then prep format-specific only for invites you actually receive — don't prep all three before any invite arrives. It's rare to be invited to all three in the same cycle.
You failed Solve and are reapplying
Prep specifically for the firm you're reapplying to. Failure is rarely a "general problem-solving" issue — it's a specific format gap. Diagnose with a fresh free PSG diagnostic before drilling.
Frequently asked questions
Are McKinsey, BCG, and Bain assessments equally difficult?
They're hard in different ways. McKinsey Solve is the longest and most cognitively varied (three distinct mini-games). BCG Casey is the most communication-heavy — you write structured responses to a chatbot in real time. Bain SOVA is the most aptitude-style — closer to a classic numerical/verbal/situational online assessment. None is meaningfully 'easier' than the others; difficulty depends on which format suits your strengths.
Does passing one MBB assessment help you with the others?
Skill transfer is real but partial. Structured problem-solving, fast data/exhibit reading, and judgment under ambiguity carry across all three. Format-specific muscle (ecosystem trait matching for Solve, written chatbot pacing for Casey, SOVA-style aptitude reps for Bain) does not. Plan on light format-specific prep for each firm you've been invited to.
Can you retake an MBB assessment?
Generally one attempt per application cycle, at all three firms. Reapplying typically opens a new attempt after 12–24 months depending on office and policy. None of the three publish official retake windows — confirm with the recruiter who issued your invite.
Do all three MBB firms use AI or game-based assessments now?
All three use some form of digital assessment, but the formats are different. McKinsey Solve is game-based (the most 'simulation' of the three). BCG Casey is chatbot-based written case. Bain SOVA blends classic aptitude (numerical, verbal) with situational judgment. None is a traditional written test alone in 2026.
Which MBB assessment is hardest?
Median candidate reports put McKinsey Solve as the most demanding overall — purely because it's longest (~70 min), most cognitively varied, and has the most format-specific gotchas like the 20%-per-undesired-trait scoring on Sea Wolf. But for candidates who are weak writers under time pressure, BCG Casey is harder. For candidates rusty on numerical aptitude, Bain SOVA bites worst. 'Hardest' depends on the candidate.
Prep the one we actually specialise in
We're honest about not building Casey or SOVA simulators. McKinsey Solve is what SolvePrep is built for — full 2026 format, three mini-games, free tier, per-game scoring review on Elite.