McKinsey SFL Classic: 13-Decision Practice Simulation

What is the McKinsey Sustainable Futures Lab?

The Sustainable Futures Lab (SFL) is the judgment and prioritization game that candidates report as the third module of McKinsey Solve, after Red Rock and Sea Wolf. There is no calculator and no data exhibit: you rank actions, then make linked decisions about a sustainability project, its team and its stakeholders. In 2026 there are two reported versions. Candidates with an 85-minute invitation describe a 20-minute SFL of about 13 decisions. Since late August 2026, some candidates with a 95-minute invitation describe a new, roughly 30-minute SFL in which you lead a team of four researchers over three simulated days. McKinsey has published neither format, so everything below is labelled by how we know it, checked October 2, 2026.

Which SFL version will you get?

Read the total time in your invitation email. McKinsey's Solve FAQ says the length of your assessment is in that email and that each task starts with an untimed tutorial. Candidate and prep-provider reports then map the length to the games like this:

85-minute invitation: the standard SFL

35

30

20

• Red Rock
• Sea Wolf
• Standard SFL
• Total 85 min

95-minute invitation: the new 30-minute SFL

35

30

30

• Red Rock
• Sea Wolf
• New SFL
• Total 95 min

Three facts matter more than the map itself.

• Both versions are live at the same time. On one PrepLounge thread, a candidate in the Middle East asked about a 95-minute invite on August 24, 2026, another candidate there sat an 85-minute invite on August 25, and on September 11 a candidate who had taken it reported a new 30-minute SFL with a "much more complex interface". Prep sites tracking candidate reports (Solve Games Guide, SolvePrep, PrepMatter) described both versions as active through late September.
• The 95-minute version is best treated as a pilot. It is weeks old, no region pattern has been established, and McKinsey has made no announcement. It could become the standard, change again, or be withdrawn.
• Some older advice is wrong on both sides. Several coaches answered in late August that the extra 10 minutes were buffer time; the September report contradicts that. One prep guide says the 13-question SFL was retired, yet 85-minute invitations kept arriving after that claim.

If your email says 65 minutes, you will not sit SFL, so spend your time on Red Rock and Sea Wolf. If it says 85, practise the standard SFL below. If it says 95, read the new-version section and still practise the standard one: the judgment it trains is the same.

How does standard SFL differ from the new 30-minute SFL?

The skills overlap more than the screens do. Both versions reward setting a clear objective first, spending scarce attention on the facts that change the decision, updating when new evidence lands, and keeping people on side without giving up the plan.

For the standard format in Road to Offer, paid Learning mode shows feedback after each decision and lets you retry a missed decision.

What is officially known, and what is candidate-reported?

Most confident SFL content online blurs these categories. Keep them apart.

How does the standard 20-minute SFL work?

Prep-provider write-ups agree on the shape: a short project brief, then one ranking question, then about a dozen scenario questions that follow the same project from kickoff to recommendation. Each option is a full sentence describing a course of action, and later questions build on what happened earlier, so the run reads as one story rather than 13 quizzes.

Road to Offer's free SFL simulation follows this standard format: 13 linked decisions on one project, starting with a ranking task, with every decision reviewed when you finish. It is original practice, not a copy of the live module.

How does the new 30-minute SFL work (reported)?

This is the version candidates describe in 95-minute invitations. The step-by-step detail below comes from prep providers who reconstructed it from candidate reports (PrepMatter, which says it sat the redesigned assessment in September 2026, and Solve Games Guide); McKinsey has not confirmed any of it.

You lead a field research lab with four researchers who have different specialisms and four workstations that need staffing. After a tutorial and onboarding, the game runs three project days, and each day opens with a goal: reports describe Day 1 centred on the researchers' needs, Day 2 on the workstations' needs, and Day 3 on balancing both. Each day repeats four stages.

Reports agree the instructions are text only, with no calculator or exhibits, and that answers are recorded in a notes panel you can scroll back through. The scarce information requests are the main difference in feel: in the standard version every fact is on screen, while here you choose which facts to buy.

How Road to Offer covers it: the new format has its own practice, SFL Island, with its own guide: Practice 1 is a full free Simulation run with a worked debrief, and practices 2 to 10 come with the SFL pack. The same pack opens the 11 SFL Classic simulations on this page.

What do both versions actually test?

Strip away the sustainability framing and SFL is testing three things.

The first is whether you can apply a stated decision rule. A prioritization item hands you explicit criteria and then offers an option that feels important but scores poorly against them. Candidates who rank on instinct lose points to candidates who compute the criteria first.

The second is whether you treat constraints as constraints. When one initiative cannot begin until another is delivered, or a researcher cannot work a station without the right skill, that dependency is a hard rule, not a tie-breaker.

The third is whether you can handle disagreement without either capitulating or stalling. A stakeholder or researcher objects and offers no new data. Reordering to keep the peace makes the process arbitrary; going quiet lets the problem grow. The stronger move is to acknowledge the concern, show the evidence and create a concrete route forward. It is the same disposition McKinsey probes in the Personal Experience Interview.

How do you rank initiatives in SFL-style questions?

Compute the criterion the prompt names, apply tie-breakers only to ties, then enforce dependencies.

1. Identify the primary metric. If the brief says residents protected per dollar, calculate that ratio for every initiative before ranking. Dividing by the right denominator is the instinct that market sizing drills and mental math drills build.
2. Apply the tie-breaker only to ties. Do not let a fast project jump ahead of a more efficient one when speed is only the second rule.
3. Enforce dependencies as hard constraints. A dependent initiative cannot precede its prerequisite, even if its standalone score is attractive.
4. Review the complete order. Check each adjacent pair and every dependency before confirming.

Here is the method on an original example. A town ranks five flood initiatives by residents protected per $1M, and the volunteer alert network cannot run without the warning app.

Compute the ratio first, then apply the dependency

1. Volunteer alert network9,000 ÷ $0.3M = 30,000
2. Warning app10,000 ÷ $0.5M = 20,000
3. Culvert clearing6,000 ÷ $0.6M = 10,000
4. Levee raise18,000 ÷ $3.6M = 5,000
5. Pump station3,000 ÷ $1.5M = 2,000

Warning app → Volunteer alert network. The network has the best ratio but needs the app, so the app moves above it.

Check your ranking

Final order

1. Warning app
2. Volunteer alert network
3. Culvert clearing
4. Levee raise
5. Pump station

The levee protects the most residents in total but ranks fourth: 18,000 residents for $3.6M is 5,000 per $1M.

How do you answer SFL stakeholder and team questions?

Use three moves: acknowledge, evidence, action.

• Acknowledge the legitimate concern without abandoning the decision.
• Show the evidence and criteria that produced the choice.
• Offer a concrete action, such as validating one assumption, agreeing an update time or trialling a reassignment for one day.

The weak extremes are capitulation and delay. In the new version the same rule applies to your researchers: a dilemma answered by doing whatever the researcher asks, or by ignoring them, both cost you. Answer the actual problem and keep the day's goal visible.

What are the common SFL decision traps?

When reviewing a mistake, name the trap and rewrite the decision using the prompt's actual rule. That transfers better than memorizing which option was correct in one scenario.

How should you prepare in the two weeks before your assessment?

Practise under the time your own invitation states, keep the decision rule visible, and follow the live tutorial over any guide, this one included.

How does SFL fit with the other Solve games?

In every reported invitation that includes SFL, you also sit Red Rock and Sea Wolf, and you switch methods between them. Sea Wolf is constraint satisfaction: filter microbes against disqualifying rules, then build a set whose averages meet every threshold. Red Rock is exhibit reading and calculation, where the traps are units, fixed costs and irrelevant-but-true facts. SFL has the least computation and the most instinct-versus-criteria conflict.

The Red Rock study guide goes phase by phase, and the umbrella McKinsey Solve guide covers how the assessment sits in McKinsey's process. All six firm assessment simulations Road to Offer publishes are on the assessment simulators page, and the McKinsey case interview guide covers the live rounds Solve is a gate for.

McKinsey and Solve are trademarks of McKinsey & Company. Road to Offer is independent and is not endorsed by McKinsey. Sources checked October 2, 2026: McKinsey's Solve FAQ (August 2025), PrepLounge thread 25242 (August 24 to September 11, 2026), and prep-provider reconstructions from Solve Games Guide, SolvePrep and PrepMatter, which we treat as reports rather than authority.