The McKinsey Solve assessment: what it is, what's in it, and how to prepare

What Solve is

Solve is an online assessment McKinsey sends to most consulting applicants before any interview. It's a set of ecology-themed games rather than a test of business knowledge: you analyse data on an island study, pick microbes to clean up the ocean, and (on some invitations) lead a research team through a run of judgement calls. McKinsey's own page says there's no need to prepare and to approach it with curiosity. Most candidates prepare anyway, and one prep site reports that the survey at the end now asks how many hours you spent preparing.

The names you'll see: McKinsey Solve is the current name. Problem Solving Game (PSG) was used around 2020 to 2022. Imbellus was the company that built the original version. McKinsey Digital Assessment is an older label McKinsey itself used. They all mean this test; the names and what changed in each era has the detail.

Where it sits in the process

Application first, then a quick screen, then the Solve invitation, then McKinsey reviews your Solve result together with the rest of your application before deciding on interviews. McKinsey's own page says the result is considered alongside the rest of your application, not on its own. Prep sites report that most invitations give a one to two week window and that only a minority of candidates who take Solve go on to interviews, but McKinsey publishes no pass rate and no cutoff, so treat any specific percentage you read as an estimate.

The rules, from McKinsey's page: no applications, websites, AI tools or pre-prepared notes during the assessment, no screenshots or recording, and you sit it alone. Practising beforehand is fine. Using help during it is not.

Your invitation and the timings

The single most useful thing in your invitation email is the total length. It tells you which games you'll get.

Each game runs on its own clock, so time saved in one can't be spent in another. Candidates report roughly 35 minutes for Red Rock and 30 for Sea Wolf; the tutorial before each game is untimed. Our Red Rock simulator runs a 35-minute clock to match. More detail, including where the reports disagree, in what your invitation length means.

What changed in 2026

• The Sustainable Futures Lab arrived in March 2026 as a third game on 85-minute invitations: 13 prompts, about 20 minutes, no arithmetic.
• A redesigned Sustainable Futures Lab appeared in September 2026 on 95-minute invitations, according to candidates and two prep sites that describe sitting it: a 30-minute, three-day team simulation. Sources disagree on whether it has replaced the original everywhere, and some think it's a pilot. Our simulator covers the original format. The Sustainable Futures Lab guide covers both.
• Ecosystem Building is gone. It was dropped from the live assessment in 2025. A lot of prep material, and most YouTube walkthroughs, still treat it as current. Don't spend your week on it. We keep a legacy version as a reasoning drill, clearly labelled.

The games

1. Red Rock Study

Data analysis under a clock. You work a case set on Redrock Island through three one-way phases (Investigation, Analysis, Report), then answer six short cases. The whole thing is arithmetic, and what costs points is pacing and bookkeeping, not hard math. Read the Red Rock Study guide or try the simulator (one scenario free).

2. Sea Wolf

An optimisation game, also called the Ocean Cleanup or Ocean Treatment game. Three contaminated sites, and for each you pick three microbes whose combined profile meets the site's targets. The trap is that sites are scored on the average of your three picks, not on each one. Read the Sea Wolf guide or try the simulator (one scenario free).

3. Sustainable Futures Lab

The judgement game. No numbers; you lead an environmental research team and make decisions where several options sound reasonable. It exists in two versions depending on your invitation length. Read the Sustainable Futures Lab guide or try the simulator (Pro; original format).

How it's scored

McKinsey doesn't publish the scoring, the weighting between games, or a pass mark. Two things are consistently reported by prep sites and candidates. First, there's a product score: were your answers right, did your treatments meet the targets. Second, there's a process score: the assessment records how you got there, which values you collected, what you changed, how you paced yourself. McKinsey's own page says the result is weighed with the rest of your application.

What that means in practice: don't guess wildly and don't thrash. Work through each screen in a way you could explain, use the tools you're given (the calculator, the journal), and commit to answers rather than flipping between them. A clean process with a couple of wrong answers is reported to do better than a messy one with the same score. More on what is and isn't known, and what a practice score means, in McKinsey Solve scores, and how 265 practice runs on SolveForge actually scored in McKinsey Solve practice scores.

How to prepare in a week

Most people get about a week. Here's how we'd spend it.

1. Day 1: find out what you're getting. Check the invitation length against the table above. Read the guide for each game you'll face. Skip Ecosystem.
2. Days 2 to 3: learn the mechanics. Play each game once, slowly, to learn the interface and the one-way steps. The point of a first run is to stop the interface costing you attention on the day. Red Rock and Sea Wolf have free scenarios here and elsewhere.
3. Days 4 to 5: fix the traps. Red Rock: percentage points versus percent, medians versus means, totals versus subgroups. Sea Wolf: the averaging shortcut and the undesired trait. Sustainable Futures Lab: pick a posture and hold it.
4. Day 6: one timed run of everything, in order. Fresh scenarios if you can get them; a replay tells you about your memory, not your readiness. Our full timed mock does this for the 65 and 85-minute invitations.
5. Day 7: rest. Do McKinsey's technical check, sort out a quiet room, and stop. The Solve checklist has the day-before and test-day steps in one printable page.

On the day

Take the untimed tutorials slowly. Prep sites report that pen and paper are fine; what McKinsey's page rules out is apps, websites, pre-prepared notes and AI tools. Read the whole screen before touching anything, because in Red Rock and Sea Wolf a confirmed step doesn't reopen. If something goes wrong technically, McKinsey's page lists a support address; use it rather than restarting on your own.