mckinsey problem solving tests

McKinsey Solve

• Fundamentals
• How it works
• Skills tested
• How to prepare
• A guide to the McKinsey Problem Solving Game

MCC is here to help

McKinsey’s Solve assessment has been making candidates sweat ever since it was initially trialled at the firm’s London office back in 2017 - and things have gotten even more difficult since a new version launched in Spring 2023, adding the Redrock case study.

More recently, in Summer 2023, we have seen a new iteration of that Redrock case, as we continue to interview test takers to keep you updated. This replaces the case study about optimising wolf pack populations across Redrock Island with one about boosting the overall plant biodiversity on the same island.

Since its initial roll-out, the Solve assessment has definitely been the most idiosyncratic, but also the most advanced, of the screening tests used by the MBB firms.

It can be hard to understand how an ecology-themed video game can tell McKinsey whether you’ll make a good management consultant, let alone know how to prepare yourself to do well in that game. When you consider that McKinsey are potentially cutting 70%+ of the applicant pool based on this single test, you can hardly blame applicants for being worried.

Matters are definitely not helped by the dearth of reliable, up-to-date information about what could very well be - with a top-tier consulting job on the line - the most important test you will take over your entire career. This was already true with the version of Solve that had been around for a few years, let alone the new iterations.

What information is available online is then often contradictory. For a long time, there was huge disagreement as to whether it is actually possible to meaningfully prepare for the Solve assessment - before you’ve even considered how to go about that preparation. There is also a lot of confusion and inaccuracy around the new Redrock case - largely as it is such a recent addition, and individual test takers tend to misremember details.

Luckily, we at MCC have been interviewing test takers both before and after the Redrock case rollout and have been following up to see which strategies and approaches actually work to push individuals through to interview.

Here, we’ll explain that it is indeed possible to prepare effectively for both versions of Solve and give you some ideas for how you can get started. Understanding how the Solve assessment works, what it tests you for and how is critical for all but the most hurried preparations.

This article makes for a great introduction to the Solve assessment. However, if you are going to be facing this aptitude test yourself and want full information and advice for preparation, then you should ideally get our full PDF guide:

Master the Solve Assessment

What is the mckinsey solve assessment.

In simple terms, the McKinsey Solve assessment is a set of ecology-themed video games. In these games, you must do things like build food chains, protect endangered species, manage predator and prey populations, boost biodiversity and potentially diagnose diseases within animal populations or identify natural disasters.

Usually, you will be given around 70 minutes to complete two separate games, spending about the same amount of time on each.

Until recently, these games had uniformly been Ecosystem Building and Plant Defence. However, since Spring 2023, McKinsey has been rolling out a new version across certain geographies. This replaces the Plant Defence game with the new Redrock case study. Some other games have also been run as tests.

We’ll run through a little more on all these games below to give you an idea of what you’ll be up against for both versions and possible new iterations.

An important aspect that we'll cover in more detail here is that the Solve games don't only score you on your answers (your "product score"), but also on the method you use to arrive at them (your "process score") - considerably impacting optimal strategy.

In the past, candidates had to show up to a McKinsey office and take what was then the Digital Assessment or PSG on a company computer. However, candidates are now able to take the re-branded Solve assessment at home on their own computers.

Test takers are allowed to leverage any assistance they like (you aren’t spied on through your webcam as you would be with some other online tests), and it is common to have a calculator or even another computer there to make use of.

Certainly, we strongly advise every candidate to have at least a pen, paper and calculator on their desk when they take the Solve assessment.

Common Question: Is the Solve assessment the same thing as the PSG?

In short, yes - “Solve” is just the newer name for the McKinsey Problem Solving Game.

We want to clear up any potential confusion right at the beginning. You will hear this same screening test called a few different things in different places. The Solve moniker itself is a relatively recent re-branding by McKinsey. Previously, the same test was known as either the Problem Solving Game (usually abbreviated to PSG) or the Digital Assessment. You will also often see that same test referred to as the Imbellus test or game, after the firm that created the first version.

You will still see all these names used across various sites and forums - and even within some older articles and blog posts here on MyConsultingCoach. McKinsey has also been a little inconsistent on what they call their own assessment internally. Candidates can often become confused when trying to do their research, but you can rest assured that all these names refer to the same screening test - though, of course, folk might be referring to either the legacy or Redrock versions.

How and why does McKinsey use the Solve assessment?

It’s useful to understand where the Solve assessment fits into McKinsey’s overall selection process and why they have felt the need to include it.

Let’s dive right in…

How is the Solve Assessment used by McKinsey?

McKinsey's own account of how the Solve assessment is used in selection can be seen in the following video:

Whilst some offices initially stuck with the old PST, the legacy Solve assessment was soon rolled out globally and given universally to candidates for roles at pretty well every level of the hierarchy. Certainly, if you are a recent grad from a Bachelor’s, MBA, PhD or similar, or a standard experienced hired, you can expect to be asked to complete the Solve assessment.

Likewise, the new Redrock case study versions seem to be in the process of being rolled out globally - though at this point it seems you might be given either (especially as McKinsey has been having significant technical problems with this new online case study) and so should be ready for both.

At present, it seems that only those applying for very senior positions, or perhaps those with particularly strong referrals and/or connections, are allowed to skip the test. Even this will be office-dependent.

As noted above, one of the advantages of the Solve assessment is that it can be given to all of McKinsey’s hires. Thus, you can expect to be run into the same games whether you are applying as a generalist consultant or to a specialist consulting role - with McKinsey Digital , for example.

The takeaway here is that, if you are applying to McKinsey for any kind of consulting role, you should be fully prepared to sit the Solve Assessment!

Where does the Solve assessment fit into the recruitment process?

You can expect to receive an invitation to take the Solve assessment shortly after submitting your resume.

It seems that an initial screen of resumes is made, but that most individuals who apply are invited to take the Solve assessment.

Any initial screen is not used to make a significant cut of the candidate pool, but likely serves mostly to weed out fraudulent applications from fake individuals (such as those wishing to access the Solve assessment more than once so they can practice...) and perhaps to eliminate a few individuals who are clearly far from having the required academic or professional background, or have made a total mess of their resumes.

Your email invitation will generally give you either one or two weeks to complete the test, though our clients have seen some variation here - with one individual being given as little as three days.

Certainly, you should plan to be ready to sit the Solve assessment within one week of submitting your resume!

Once you have completed the test, McKinsey explain on their site that they look at both your test scores and resume (in more detail this time) to determine who will be invited to live case interviews. This will only be around 30% of the candidates who applied - possibly even fewer.

One thing to note here is that you shouldn’t expect a good resume to make up for bad test scores and vice versa. We have spoken to excellent candidates whose academic and professional achievements were not enough to make up for poor Solve performance. Similarly, we don’t know of anyone invited to interview who hadn’t put together an excellent resume.

Blunty, you need great Solve scores and a great resume to be advanced to interview.

Your first port of call to craft the best possible resume and land your invitation to interview is our excellent free consulting resume guide .

Why does this test exist?

As with Bain, BCG and other major management consulting firms, McKinsey receives far far more applications for each position than they can ever hope to interview. Compounding this issue is that case interviews are expensive and inconvenient for firms like McKinsey to conduct. Having a consultant spend a day interviewing just a few candidates means disrupting a whole engagement and potentially having to fly that consultant back to their home office from wherever their current project was located. This problem is even worse for second-round interviews given by partners.

Thus, McKinsey need to cut down their applicant pool as far as possible, so as to shrink the number of case interviews they need to give without losing the candidates they actually want to hire. Of course, they want to accomplish this as cheaply and conveniently as possible.

The Problem Solving Test (invariably shortened to PST) had been used by McKinsey for many years. However, it had a number of problems that were becoming more pronounced over time, and it was fundamentally in need of replacement. Some of these were deficiencies with the test itself, though many were more concerned with how the test fitted with the changing nature of the consulting industry.

The Solve assessment was originally developed and iterated by the specialist firm Imbellus ( now owned by gaming giant Roblox ) to replace the long-standing PST in this screening role and offers solutions to those problems with its predecessor.

We could easily write a whole article on what McKinsey aimed to gain from the change, but the following few points cover most of the main ideas:

• New Challenges: Previously, candidates were largely coming out of MBAs or similar business-focussed backgrounds and the PST’s quickfire business questions were thus perfectly sufficient to select for non-technical generalist consulting roles. However, as consulting projects increasingly call for a greater diversity and depth of expertise, McKinsey cannot assume the most useful talent – especially for technical roles – is going to come with pre-existing business expertise. A non-business aptitude test was therefore required.
• Fairness and the Modern Context: The covid pandemic necessitated at-home aptitude testing. However, even aside from this, online testing dramatically reduces the amount of travel required of candidates. This allows McKinsey to cast a wider net, providing more opportunities to those living away from hub cities, whilst also hugely reducing the carbon footprint associated with the McKinsey selection process.
• Gaming the System: More pragmatically, the Solve assessment is a much harder test to “game” than was the PST, where highly effective prep resources were available and readily allowed a bad candidate with good preparation to do better than a good candidate. The fact that game parameters change for every individual test taker further cuts down the risk of candidates benefitting from shared information. The recent move towards the Redrock version then also helps McKinsey stay ahead of those developing prep resources for the legacy Solve assessment.
• Cost Cutting: A major advantage of scrapping the old pen-and-paper PST is that the formidable task of thinning down McKinsey’s applicant pool can be largely automated. No test rooms and invigilation staff need to be organised and no human effort is required to devise, transport, catalogue and mark papers.

Impress your interviewer

There has been a bit of variation in the games included in the Solve assessment/PSG over the years and what specific form those games take. Imbellus and McKinsey had experimented with whole new configurations as well as making smaller, iterative tweaks over time. That being said, the new 2023 Redrock case studies (seemingly added by McKinsey themselves without Imbellus) are by far the largest change to Solve since that assessment's genesis back in 2017.

Given that innovation seems to continue (especially with the lengthy feedback forms some candidates are being asked to fill in after sitting the newest iteration), there is always the chance you might be the first to receive something new.

However, our surveys of, and interviews with, those taking the Solve assessment - both before and after recent changes - mean we can give you a good idea of what to expect if you are presented with either the legacy or one of the Redrock versions of Solve.

We provide much more detailed explanation of each of the games in our Solve Assessment PDF Guide - including guidance on optimal scenarios to maximise your performance. Here, though, we can give a quick overview of each scenario:

Ecosystem Building

In this scenario, you are asked to assemble a self-sustaining ecosystem in either an aquatic, alpine or jungle environment (though do not be surprised if environments are added, as this should be relatively easy to do without changing the underlying mechanics).

The game requires you to select a location for your ecosystem. Several different options are given, all with different prevailing conditions. You then have to select a number of different plant and animal species to populate a functioning food chain within that location.

In previous versions of the game, you would have had to fit as many different species as possible into a functioning food chain. However, newer iterations of the Solve assessment require a fixed number of eight or, more recently, seven species to be selected.

Species selection isn’t a free-for-all. You must ensure that all the species you select are compatible with one another - that the predator species you select are able to eat the prey you have selected for them etc. All the species must also be able to survive in the conditions prevailing at the location you have selected.

So far, this sounds pretty easy. However, the complexity arises from the strict rules around the manner and order in which the different species eat one another. We run through these in detail in our guide, with tips for getting your food chain right. However, the upshot is that you are going to have to spend some significant time checking your initial food chain - and then likely iterating it and replacing one or more species when it turns out that the food chain does not adhere to the eating rules.

Once you have decided on your food chain, you simply submit it and are moved on to the next game. In the past, test takers were apparently shown whether their solution was correct or not, but this is no longer the case.

Test takers generally report that this game is the easier of the two, whether it is paired with the Plant Defence game in the legacy Solve or the Redrock case study in the new version. Candidates will not usually struggle to assemble a functioning ecosystem and do not find themselves under enormous time pressure. Thus, we can assume that process scores will be the main differentiator between individuals for this component of the Solve assessment.

For ideas on how to optimise your process score for this game, you can see our PDF Solve guide .

Plant Defence

As mentioned, this game has been replaced with the Redrock case study in the new newer version of the Solve assessment, rolled out from Spring 2023 and further iterated in Summer 2023. However, you might still be asked to sit the legacy version, with this game, when applying to certain offices - so you should be ready for it!

This scenario tasks you with protecting an endangered plant species from invasive species trying to destroy it.

The game set-up is much like a traditional board game, with play taking place over a square area of terrain divided into a grid of the order of 10x10 squares.

Your plant is located in a square near the middle of the grid and groups of invaders - shown as rats, foxes or similar - enter from the edges of the grid before making a beeline towards your plant.

Your job then is to eliminate the invaders before they get to your plant. You do this by placing defences along their path. These can be terrain features, such as mountains or forests, that either force the invaders to slow down their advance or change their path to move around an obstacle. To actually destroy the invaders though, you use animal defenders, like snakes or eagles, that are able to deplete the groups of invaders as they pass by their area of influence.

Complication here comes from a few features of the game. In particular:

• You are restricted in terms of both the numbers of different kinds of defenders you can use and where you are allowed to place them. Thus, you might only have a couple of mountains to place and only be allowed to place these in squares adjacent to existing mountains.
• The main complication is the fact that gameplay is not dynamic but rather proceeds in quite a restricted turnwise manner. By this, we mean that you cannot place or move around your defences continuously as the invaders advance inwards. Rather, turns alternate between you and invaders and you are expected to plan your use of defences in blocks of five turns at once, with only minimal allowance for you to make changes on the fly as the game develops.

The plant defence game is split into three mini-games. Each mini-game is further split into three blocks of five turns. On the final turn, the game does not stop, but continues to run, with the invaders in effect taking more and more turns whilst you are not able to place any more defences or change anything about your set-up.

More and more groups of invaders pour in, and your plant will eventually be destroyed. The test with this “endgame” is simply how many turns your defences can stand up to the surge of invaders before they are overwhelmed.

As opposed to the Ecosystem Building scenario, there are stark differences in immediate candidate performance - and thus product score - in this game. Some test takers’ defences will barely make it to the end of the standard 15 turns, whilst others will survive 50+ turns of endgame before they are overwhelmed.

In this context, as opposed to the Ecosystem Building game typically preceding it, it seems likely that product score will be the primary differentiator between candidates.

We have a full discussion of strategies to optimise your defence placement - and thus boost your product score - in our Solve guide .

Redrock Case Study

This is the replacement for the Plant Defence game in the newest iteration of Solve.

One important point to note is that, where the Solve assessment contains this case study, you have a strict, separate time limit of 35 minutes for each half of the assessment. You cannot finish one game early and use the extra time in the other, as you could in the legacy Solve assessment.

McKinsey has had significant issues with this case study, with test takers noting several major problems. In particular:

• Glitches/crashes - Whilst the newest, Summer 2023 version seems to have done a lot to address this issue, many test takers have had the Redrock case crash on them. Usually, this is just momentary and the assessment returns to where it was in a second or two. If this happens to you, try to just keep calm and carry on. However, there are reports online of some candidates having the whole Solve assessment crash and being locked out as a result. If this happens, contact HR.
• Poor interface - Even where there are no explicit glitches, users note that several aspects of the interface are difficult to use and/or finicky, and that they generally seem poorly designed compared to the older Ecosystem Building game preceding it. For example, test takers have noted that navigation is difficult or unclear and the drag and drop feature for data points is temperamental - all of this costing precious time.
• Confusing language - Related to the above is that the English used is often rather convoluted and sometimes poorly phrased. This can be challenging even for native English speakers but is even worse for those sitting Solve in their second language. It can make the initial instructions difficult to understand - compounding the previous interface problem. It can also make questions difficult, requiring a few readings to comprehend.
• Insufficient time - Clearly, McKinsey intended for Redrock to be time pressured. Whilst the newest, Summer 2023 iteration of the Redrock case seems slightly more forgiving in this regard, time is still so scarce that many candidates don't get through all the questions. This is plainly sub-optimal for McKinsey - as well as being stressful and disheartening for candidates. We would expect further changes to be made to address this issue in future.

McKinsey are clearly aware of these issues, as even those sitting the new version of Redrock have been asked to complete substantial feedback surveys. Do note, then, that this raises the likelihood of further changes to the Redrock case study in the near term - meaning you should always be ready to tackle something new.

For the time being, though, we can take you through the fundamentals of the current version of the Redrock case study. For more detail, see our freshly updated PDF Guide .

The Scenario

Whilst changes to the details are likely in future, the current Redrock case study is set on the Island of Redrock. This island is a nature reserve with populations of various species, including wolves, elk and several varieties of plant.

In the original Redrock case, it is explained that the island's wolves are split into four packs, associated with four geographical locales. These packs predate the elk and depend upon them for food, such that there is a dynamic relationship between the population numbers of both species. Your job is to ensure ecological balance by optimising the numbers of wolves in the four packs, such that both wolves and elk can sustainably coexist.

In the newer iteration of the case, first observed in Summer 2023, you are asked to assess which, if any, of three possible strategies can successfully boost the island's plant biodiversity by a certain specified percentage. Plants here are segmented into grasses, trees and shrubs.

The Questions

The Redrock case study's questions were initially split into three sections, but a fourth was added later. These sections break down as follows:

• Investigation - Here, you have access to the full description of the case, with all the data on the various animal populations. Your task is to efficiently extract all the most salient data points and drag-and-drop them to your "Research Journal" workspace area. This is important, as you subsequently lose access to all the information you don't save at this stage.
• Analysis - You must answer three numerical questions using information you saved in the Investigation section. This can include you dragging and dropping values to and from an in-game calculator.
• Report - Formerly the final section, you must complete a pre-written report on the wolf populations or plant biodiversity levels, including calculating numerical values to fill in gaps and using an in-game interface to make a chart to illustrate your findings. You will leverage information saved in the Investigation section, as well as answers calculated in the Analysis section.
• Case Questions - This section adds a further ten individual case questions. These are wolf-themed, so are thematically similar to the original Redrock case, but are slightly incongruous with the newer, plant-themed version of Redrock. In both instances, though, these questions are entirely separable from the main case preceding them, not relying on any information from the previous sections. The ten questions are highly quantitative and extremely time pressured. Few test takers finish them before being timed out.

This is a very brief summary - more detail is available in our PDF Guide .

Other Games - Disease and Disaster Identification

There have been accounts of some test takers being given a third game as part of their Solve assessment. At time of writing, these third games have always been clearly introduced as non-scored beta tests for Imbellus to try out potential new additions to the assessment. However, the fact that these have been tested means that there is presumably a good chance we’ll see them as scored additions in future.

Notably, these alternative scenarios are generally variations on a fairly consistent theme and tend to share a good deal of the character of the Ecosystem Building game. Usually, candidates will be given a whole slew of information on how an animal population has changed over time. They will then have to wade through that information to figure out either which kind of natural disaster or which disease has been damaging that population - the commonality with the Ecosystem Building game being in the challenge of dealing with large volumes of information and figuring out which small fraction of it is actually relevant.

Join thousands of other candidates cracking cases like pros

What does the solve assessment test for.

Whilst information on the Solve assessment can be hard to come by, Imbellus and McKinsey have at least been explicit on what traits the test was designed to look for. These are:

• Critical Thinking : making judgements based on the objective analysis of information
• Decision Making : choosing the best course of action, especially under time pressure or with incomplete information
• Metacognition : deploying appropriate strategies to tackle problems efficiently
• Situational Awareness : the ability to interpret and subsequently predict an environment
• Systems Thinking : understanding the complex causal relationships between the elements of a system

Equally important to understanding the raw facts of the particular skillset being sought out, though, is understanding the very idiosyncratic ways in which the Solve assessment tests for these traits.

Let's dive deeper:

Process Scores

Perhaps the key difference between the Solve assessment and any other test you’ve taken before is Imbellus’s innovation around “process scores”.

To explain, when you work through each of the games, the software examines the solutions you generate to the various problems you are faced with. How well you do here is measured by your “product score”.

However, scoring does not end there. Rather, Solve's software also constantly monitors and assesses the method you used to arrive at that solution. The quality of the method you used is then captured in your “process score”.

To make things more concrete here, if you are playing the Ecosystem Building game, you will not only be judged on whether the ecosystem you put together is self-sustaining. You will also be judged on the way you have worked in figuring out that ecosystem - presumably, on how efficient and organised you were. The program tracks all your mouse clicks and other actions and will thus be able to capture things like how you navigate around the various groups of species, how you place the different options you select, whether you change your mind before you submit the solution and so on.

You can find more detail on these advanced aspects of the Solve assessment and the innovative work behind it in the presentation by Imbellus founder Rebecca Kantar in the first section of the following video:

Compared to other tests, this is far more like the level of assessment you face from an essay-based exam, where the full progression of your argument towards a conclusion is marked - or a maths exam, where you are scored on your working as well as the final answer (with, of course, the major advantage that there is no highly qualified person required to mark papers).

Clearly, the upshot of all this is that you will want to be very careful how you approach the Solve assessment. You should generally try to think before you act and to show yourself in a very rational, rigorous, ordered light.

We have some advice to help look after your process scores in our PDF Guide to the McKinsey Solve Assessment .

A Different Test for Every Candidate

Another remarkable and seriously innovative aspect of the Solve assessment is that no two candidates receive exactly the same test.

Imbellus automatically varies the parameters of their games to be different for each individual test taker, so that each will be given a meaningfully different game to everyone else’s.

Within a game, this might mean a different terrain setting, having a different number of species or different types of species to work with or more or fewer restrictions on which species will eat which others.

Consequently, even if your buddy takes the assessment for the same level role at the same office just the day before you do, whatever specific strategy they used in their games might very well not work for you.

This is an intentional feature designed to prevent test takers from sharing information with one another and thus advantaging some over others. At the extreme, this feature would also be a robust obstacle to any kind of serious cheating.

To manage to give every candidate a different test and still be able to generate a reliable ranking of those candidates across a fundamental skillset, without that test being very lengthy, is a considerable achievement from Imbellus. At high level, this would seem to be approximately equivalent to reliably extracting a faint signal from a very noisy background on the first attempt almost every time.

(Note that we are yet to confirm to what extent and how this also happens with the new Redrock case studies, but it seems to be set up to allow for easy changes to be made to the numerical values describing the case, so we assume there will be similar, widespread of variation.)

Preparation for the McKinsey Solve assessment

Understanding what the Solve assessment tests for immediately begs the question as to whether it is possible to usefully prepare and, if so, what that preparation should look like.

Is it Really Possible to Prepare for the McKinsey Solve Assessment?

In short, yes you can - and you should!

As noted previously, there has been a lot of disagreement over whether it is really possible to prep for the Solve assessment in a way that actually makes a difference.

Especially for the legacy version, there has been a widespread idea that the Solve assessment functions as something like an IQ test, so that preparation beyond very basic familiarisation to ensure you don’t panic on test day will not do anything to reliably boost your scores (nobody is going to build up to scoring an IQ of 200 just by doing practice tests, for example).

This rationale says that the best you can do is familiarise yourself with what you are up against to calm your nerves and avoid misunderstanding instructions on test day. However, this school of thought says there will be minimal benefit from practice and/or skill building.

The utility of preparation has become a clearer with the addition of the Redrock case study to the new version of Solve. Its heavily quantitative nature, strong time pressure and structure closely resembling a traditional business case make for a clearer route to improvement.

However, as we explain in more detail in our PDF guide to the Solve assessment, the idea that any aspect of either version of Solve can't be prepared for has been based on some fundamental misunderstandings about what kind of cognitive traits are being tested. Briefly put, the five key skills the Solve assessment explicitly examines are what are known as higher-order thinking skills.

Crucially, these are abilities that can be meaningfully built over time.

McKinsey and Imbellus have generally advised that you shouldn’t prepare. However, this is not the same as saying that there is no benefit in doing so. McKinsey benefits from ensuring as even a playing field as possible. To have the Solve test rank candidates based purely on their pre-existing ability, they would ideally wish for a completely unprepared population.

How to prep

We discuss how to prep for the Solve assessment in full detail in our PDF guide . Here, though, we can give you a few initial pointers to get you started. In particular, there are some great ways to simulate different games as well as build up the skills the Solve assessment tests for.

Playing video games is great prep for the legacy Solve assessment in particular, but remains highly relevant to the new Redrock version.

Contrary to what McKinsey and Imbellus have said - and pretty unfortunately for those of us with other hobbies - test takers have consistently said that they reckoned the Problem Solving Game, and now the Solve assessment, favours those with strong video gaming experience.

If you listened when your parents told you video games were a waste of time and really don’t have any experience, then putting in some hours on pretty much anything will be useful. However, the closer the games you play are to the Solve scenarios, the better. We give some great recommendations on specific games and what to look for more generally in our Solve guide - including one free-to-play game that our clients have found hugely useful as prep for the plant defence game!

PST-Style Questions

The inclusion of the Redrock case studies in the new version of Solve really represents a return to something like a modernised PST. Along with the similar new BCG Casey assessment, this seems to be the direction of travel for consulting recruitment in general.

Luckily, this means that you can leverage the wealth of existing PST-style resources to your advantage in preparation.

Our PST article - which links to some free PST questions and our full PST prep resources - is a great place to start. However, better than old-fashioned PDF question sets are the digital PST-style questions embedded in our Case Academy course . Conducted online with a strict timer running, these are a much closer approximation of the Solve assessment itself. These questions are indeed a subset of our Case Academy course, but are also available separately in our Course Exercises package .

Quick Mathematics With a Calculator and/or Excel

Again, specifically for the Redrock assessment, you will be expected to solve math problems very quickly. The conceptual level of mathematics required is not particularly high, but you need to know what you are doing and get through it fast using a calculator nand/or Excel, if you are already comfortable with that program.

Our article on consulting math is a great place to start to understand what is expected of you throughout the recruiting process, with our consulting math package (a subset of our Case Academy course) providing more in-depth lessons and practice material.

Learn to Solve Case Studies

With the Redrock case studies clearly being ecology-themed analogues to standard business case studies, it's pretty obvious that getting good at case studies will be useful.

However, the Solve assessment as a whole is developed and calibrated to be predictive of case interview performance, so you can expect that improving your case solving ability will indirectly bring up your performance across the board.

Of course, this overlaps with your prep for McKinsey's case interviews. For more on how to get started there, see the final section of this article.

Learning About Optimal Strategies for the Games

The first thing to do is to familiarise yourself with the common game scenarios from the Solve assessment and how you can best approach them to help boost your chances of success.

Now, one thing to understand is that, since the parameters for the games change for each test taker, there might not be a single definitive optimal strategy for every single possible iteration of a particular game. As such, you shouldn’t rely on just memorising one approach and hoping it matches up to what you get on test day.

Instead, it is far better to understand why a strategy is sensible in some circumstances and when it might be better to do something else instead if the version of the game you personally receive necessitates a different approach.

In this article, we have given you a useful overview of the games currently included in the Solve assessment. However, a full discussion with suggested strategies is provided in our comprehensive Solve guide .

With the limited space available here, this is only a very brief sketch of a subset of the ways you can prep.

As noted, what will help with all of these and more is reading the extensive prep guidance in our full PDF guide to the Solve assessment...

The MCC Solve Assessment Guide

Preparing for the Solve assessment doesn’t have to be a matter of stumbling around on your own. This article is a good introduction. From here, though our new, updated PDF guide to the McKinsey Solve assessment is your first stop to optimise your Solve preparation.

This guide is based on our own survey work and interviews with real test takers, as well as iterative follow-ups on how the advice in previous editions worked out in reality.

Does it make sense to invest in a guide?

Short answer: yes. If you just think about the financials, a job at McKinsey is worth millions in the long run. If you factor in experience, personal growth and exit opportunities, the investment is a no-brainer.

How our guide can help you ace the test

Don't expect some magic tricks to game the system (because you can't), but rather an in-depth analysis of key areas crucial to boost your scores. This helps you to:

As noted, the guide is based on interviews with real recent test takers and covers the current games in detail. Being familiar with the game rules, mechanics and potential strategies in advance will massively reduce the amount of new information you have to assimilate from scratch on test day, allowing you to focus on the actual problems at hand.

Despite the innovative environment, the Solve assessment tests candidates for the same skills evaluated in case interviews, albeit on a more abstract level. Our guide breaks these skills down and provides a clear route to develop them. You also benefit from the cumulative experience of our clients, as we have followed up to see which prep methods and game strategies were genuinely helpful.

A clear plan of how to prepare is instrumental for success. Our guide includes a detailed, flexible preparation strategy, leveraging a whole host of diverse prep activities to help you practice and build your skills as effectively as possible. Importantly, our guide helps you prioritise the most effective aspects of preparation to optimise for whatever timeframe you have to work in.

Overall, the MyConsultingCoach Solve guide is designed to be no-nonsense and straight to the point. It tells you what you need to know up front and - for those of you in a hurry - crucial sections are clearly marked to read first to help you prep ASAP.

For those of you starting early with more time to spare, there is also a fully detailed, more nuanced discussion of what the test is looking for and how you can design a more long-term prep to build up the skills you need - and how this can fit into your wider case interview prep.

Importantly, there is no fluff to bulk out the page count. The market is awash with guides at huge page counts, stuffed full of irrelevant material to boost overall document length. By contrast, we realise your time is better spent actually preparing than ploughing through a novel.

If this sounds right for you, you can purchase our PDF Solve guide here:

McKinsey Solve Assessment Guide

• Full guide to both the legacy version of the Solve assessment and the newer Redrock Case Study versions
• In-depth description of the different games and strategies to beat them
• Preparation strategies for the short, medium and long-term prep
• No fluff - straight to the point, with specific tips for those without much time
• Straight to your inbox
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The Next Step - Case Interviews

So, you pour in the hours to generate an amazing resume and cover letter. You prepare diligently for the Solve assessment, going through our PDF guide and implementing all the suggestions. On test day, you sit down and ace Solve. The result is an invitation to a live McKinsey case interview.

Now the real work begins…

Arduous as application writing and Solve prep might have seemed, preparing for McKinsey case interviews will easily be an order of magnitude more difficult.

Remember that McKinsey tells candidates not to prepare for Solve - but McKinsey explicitly expects applicants to have rigorously prepared for case interviews .

The volume of specific business knowledge and case-solving principles, as well as the sheer complexity of the cases you will be given, mean that there is no way around knuckling down, learning what you need to know and practicing on repeat.

If you want to get through your interviews and actually land that McKinsey offer, you are going to need to take things seriously, put in the time and learn how to properly solve case studies.

Unfortunately, the framework-based approach taught by many older resources is unlikely to cut it for you. These tend to falter when applied to difficult, idiosyncratic cases - precisely the kind of case you can expect from McKinsey!

The method MCC teaches is based specifically on the way McKinsey train incoming consultants. We throw out generic frameworks altogether and show you how to solve cases like a real management consultant on a real engagement.

You can start reading about the MCC method for case cracking here . To step your learning up a notch, you can move on to our Case Academy course .

To put things into practice in some mock interviews with real McKinsey consultants, take a look at our coaching packages .

And, if all this (rightfully) seems pretty daunting and you’d like to have an experienced consultant guide you through your whole prep from start to finish, you can apply for our comprehensive mentoring programme here .

Looking for an all-inclusive, peace of mind program?

Our comprehensive packages.

Get our Solve guide for free if you purchase any of the following packages. Just email us with your order number and we will send the guide straight to your inbox.

Access to our Case Academy and to coaching will help you prepare for Solve and for the following rounds!

The MCC bundle

• All Case Interview Course Videos
• All Case Interview Course Exercises
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• Full Access to Case Academy (Course, Exercises, Self-Assessments, Fit and Math)
• McKinsey Digital Assessment Guide
• All our PST material

Case Interview Course

• 16+ hours of lectures  covering  all aspects of the case interview
• Introduction to the consulting interview
• Case Interview foundations section 
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• Tests by Leading Employers
• Consulting Assessment Preparation
• McKinsey Problem Solving Game

McKinsey Problem Solving Game (Imbellus): a Complete Practice Guide to Pass the Digital Assessment

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There is a lot of secrecy around the McKinsey Problem Solving Game, aka Imbellus.

This gamified assessment is used to filter out a large chunk of the many McKinsey applicants, and it’s supposedly crack-proof.

The internet is packed with blog posts, Reddit discussions, and forum threads about the McKinsey PSG, some even contradicting.

This information overload coupled with the huge importance of the test makes the whole preparation process nerve-wracking.

That’s why this practice guide strives to give you accurate and easy-to-digest information about your upcoming test.

It includes:

• A complete overview of the mini-games
• The best things to keep in mind while playing them
• The most helpful practice options available right now
• Useful tips and tactics to increase your chances of passing it

So, buckle up, and let’s get started.

Find out everything you need about the  McKinsey Problem Solving Game , aka Imbellus, and prepare using actual simulations!

Gal , Expert on Game-Based Assessments at  JobTestPrep .

What is the McKinsey Problem Solving Game (PSG)?

The McKinsey Problem Solving Game, also named McKinsey Imbellus, McKinsey Digital Assessment, and Solve, is a gamified test that replaces the previous assessment, PST, in the recruiting process. The PSG consists of two mini-games lasting for 70 minutes and evaluates candidates on five key cognitive abilities.

Only candidates who pass this stage are invited to the next hiring step, the case interviews.

What Skills Does the PSG Evaluate?

The PSG evaluates the consulting traits and qualifications of a candidate and then compares them to a real McKinsey consultant. If the applicant appears similar or better than the actual consultant, they'll pass the test.

Five main thinking skills are being assessed :

• Critical Thinking : The ability to solve problems by breaking them down into smaller parts.
• Decision-Making Process : The ability to take in large amounts of information and process it efficiently to make the best possible decision within time constraints.
• Meta Cognition : The ability to monitor your cognitive processes and improve them.
• Situational Awareness : The ability to keep track of several tasks or activities concurrently.
• Systems Thinking : The ability to identify the root causes of problems and possible solutions.

Do All Candidates Get the McKinsey Problem Solving Game?

As of 2024, almost all candidates for nearly all Mckinsey offices receive the Problem Solving Game. The PST, on the other hand, is no longer in use.

Get to Know the McKinsey PSG Format Inside Out

The Problem-Solving Game is sent to candidates once they pass the initial resume screening, making it the second hiring step.

McKinsey has created five mini-games, but you'll need to take only two of them. The most common ones are Ecosysystem Building and Redrock Study , and there are four other less common mini-games that only a fraction of the applicants receive (outlined below).

The time limit for the two common mini-games is 70 minutes , and for the others, it may range between 60 to 80 minutes. Each game will also have a tutorial, which is untimed.

Now, let's dive into each of the mini-games so you'll know what to expect on the test.

• Ecosystem Building

The first mini-game you'll need to pass is Ecosystem Building. In this game, you'll be randomly placed in either a mountain ridge or a coral reef scenario.

Your main objective in this mini-game is to build a sustainable ecosystem using exactly eight species from a collection of 39 species.

To achieve this goal successfully, you must strictly follow these guidelines:

• Terrain specs : The chosen location in the ecosystem must provide suitable living conditions for all eight species.
• Calories balance : Each species must be fed with enough calories from food to sustain itself.
• Food chain continuity : Each species must not be eaten into extinction by its predators.

The gaming platform provides specific information to help you meet these guidelines (some are seen in the game's "guidebook"):

Terrain Specs

Each location in the ecosystem has seven to eight terrain specs. You can choose a location using a pinpoint.

Of these seven or eight specs, only four can be displayed at any given time, using a checklist table in the upper-right corner of the screen:

Now, here's what's crucial about these living conditions:

Each species has specific terrain specs that have to be met. If they aren't met, the species won't survive, and you won't achieve the game's main objective.

Luckily, the species' living conditions usually come in ranges, allowing you to be more flexible with the species you choose for your ecosystem.

Additionally, each species has only two to four terrain specs , when Depth/Elevation and Temperature appear for all species:

Knowing that you only need to look at specific terrain specs on the checklist table helps eliminate species or locations that are not suitable for creating a sustainable ecosystem.

Food Chain Continuity

The 39 species are divided into producers and consumers.

Producers are plants and fungi (in the Mountain scenario) and corals and seaweeds (in the Coral Reef scenario). They don't have any calorie needs, so their "calories needed" spec is always zero.

Consumers are animals that eat either plants, other animals, or both. Some consumers are at the top of the food chain and therefore not eaten by any other species.

While creating the food chain, it's important to ensure that no species is eaten to extinction. This can be monitored using the " calorie needed " and the " calorie provided " specs that each species has (shown below).

Calories Balance

Each species has a calorie needed and a calorie provided, as you can see below:

A species lives if its "calories needed" are less than the sum of the calories provided by other species it eats (other consumers or providers).

Furthermore, the species' "calories provided" must be higher than the sum of the calories needed by other species that eat it.

The Main Challenges of the Ecosystem Building Mini-Game

Ecosystem creation is first of all a decision-making game.

You get all the information you need to deliver correct decisions so there's no uncertainty or inaccurate details.

The problem is that you have a vast amount of information to absorb, calculate, analyze, and prioritize . This includes the specs of 39 species, the terrain specs of each location, and eating rules.

Some of the information is irrelevant and is there to distract you or tempt you to make assumptions . In this mini-game, you must not make any assumptions and you don't need to have any environmental, ecological, or zoological knowledge.

So, your ability to make quick and accurate calculations and ignore irrelevant data will have a great impact on your performance.

The preparation course we recommend on this page includes a replica of McKinsey's Ecosystem Building game. It enables you to practice using a like-for-like game experience and learn about every single rule, move, and item in detail. Plus, you’ll master calculation methods and other tactics to ensure the food chain survives in your chosen location.

Redrock Study

The second mini-game you'll most likely encounter is Redrock Study. 

In the game's storyline, your task is to analyze the species inhabiting an island, which includes wolves and elks. The objective of your analysis is to formulate predictions and conduct various calculations , specifically focusing on percentages, by examining data on the evolution of the animal population.

The game has 4 sections:

• Investigation   You will be presented with a written text that includes tables and graphs. Your task is to sort information and gather valuable data for the following test sections.
• Analysis   You will be presented with 3 or 4 math problems ; each is separated into two parts. You will be given a calculator and a Research Journal to gather information relevant to the questions.
• Report You will be presented with two types of questions - 
• 5 written questions regarding your findings in the analysis section
• 1 visual question in which you will need to choose a graph and use it to show what you found in the analysis.
•  Cases You will be presented with 6 to 10 questions that are unrelated to the analysis you did so far. 

You will have 35 minutes to complete all four sections , with a short, non-timed break before each one. 

Alternative Mini-Games

As of 2024, the Ecosystem Building game is constant, but the second mini-game may vary in rare cases. This means that there's a slight chance you won't get the Plant Defense mini-game, but rather one of the three we show below.

Disaster Management

In the Disaster Management game, you have to identify what type of natural disaster has happened to an animal population in an ecosystem.

Then, based on the data and information given, you need to choose a different location that will ensure the survival of the ecosystem.

The Disaster Management mini-game has only one objective - the sustainability of the ecosystem, similar to the Ecosystem Building mini-game.

Disease Management

In the Disease Management mini-game, you have to identify patterns of a disease within an ecosystem and predict who will be infected next. You can then use the information given about each species to help you solve the problem.

Migration Management

Migration Management is a turn-based puzzle game. The candidate must direct the migration of 50 animals while helping them arrive at their destination with minimal casualties and with a pre-determined amount of resources.

• Plant Defense

Plant Defense is a turn-based mini-game (similar to popular Tower Defense games). Your main objective is to defend a native plant that's located at the center of a 10x10, 10x14, or 12x12 grid from invader species, using defensive resources for as many turns as possible .

This mini-game consists of three maps, and each map is divided into two - the planning phase and the fast-forward phase. McKinsey recommends allocating 12 minutes per map, which makes it 36 minutes in total.

The 36-minute time limit is not fixed though, as it depends on how long it took you to finish the first mini-game, Ecosystem Building.

Many candidates mention that the Plant Defense game is more challenging than the Ecosystem creation. So, keep that in mind while taking the first one and plan your time wisely .

Now, let's take a closer look at the different elements and resources of this mini-game:

Your base is the native plant that you have to defend from invaders at all costs. Once an invader reaches the base, you lose the game.

Note that eventually, everyone loses, and you can't hold your base forever. But the more turns you manage to survive, the better .

There are two types of invaders in the game - Groundhog and Fox. Their movements on the map are the same, and the only difference between them is the terrain type that holds them back (more on terrains below).

Once an invader appears on your map, it will choose the shortest path to reach your base plant. This path will be shown as a yellow arrow .

There are three types of terrains in the game:

• Forest : Slows down the Groundhog for one turn
• Rocky : Slows down the Fox for one turn
• Cliff : Blocks both the Fox and the Groundhog from passing this square

Each terrain holds one grid on the map, and you cannot place terrain on a grid that already has another terrain or a defender on it (more on defenders below).

As opposed to terrains, defenders don't just slow down or block an invader, they eliminate it for good.

There are several defenders you can use in the game: Bobcat, Falcon, Wolf, Python, and Coyote.

Note that you won't see all of the defenders at once.

Each defender has two important specs you must take into account:

Range : Each defender can cover a pre-determined number of grids on the map. For example, a Python can cover only one grid, while a Falcon can cover as many as 13 grids.

Damage : Each defender can cause specific forms of damage to an invader's population. When an invader attacks, you'll be able to see its population number and the damage that your defender can cause him. A Wolf, for example, has a damaging impact of 60, while a Falcon has only 20.

The Main Challenges of the Plant Defense Mini-Game

In this mini-game, you have to make decisions based on limited information and face unexpected events (like new invaders from any direction). Also, you must achieve two simultaneous objectives - survive each of the turns separately and for as long as possible.

This is the complete opposite of the Ecosystem Building game, in which you have all the data in front of you, and you have just one objective.

Two things that can help you overcome these challenges are (1) preparing for the unexpected events that will happen during the game and (2) planning low-risk solutions based on your resources (terrains and defenders).

The prep course that we recommend on this page has the closest simulation possible to the actual Plant Defense game. It has the same gameplay, invaders, and resources, and it's based on the same algorithm that appears in the McKinsey Problem Solving Game. This will enable you to learn the most effective tactics to ensure your base plant survives as many turns as possible.

How to Beat the McKinsey Problem Solving Game?

The proven way to beat the McKinsey PSG is by properly preparing beforehand.

There's no way around it. That’s because the mini-games include an immense amount of information, rules, and patterns you must master . And they require you to use tactics and strategies that are not obvious and take time to plan and execute.

All of that is under great time pressure and the high stakes of possibly failing it and losing an opportunity to work at McKinsey.

Now, there are a few practice options you can use to get a better understanding of the PSG and improve your chances of passing it, with the PSG Interactive Simulation being the most accurate one.

McKinsey Problem Solving Game Practice Options

PSG Interactive Simulation

The  PSG Secrets simulation is an interactive platform that includes accurate practice for every part of McKinsey’s PSG. It mirrors what the actual game scenarios look like, what each button does, how the logic of the games works, how it generates the data, and more.

It has a full simulation option (two mini-games, 70 minutes), which includes:

• A full video course in 24 videos and 2h30m of content on Ecosystem, Redrock, and Plant Defense
• 2 excel solvers for the Ecosystem Game
• 10 Redrock test drills specifically for the case section
• 152 page-pdf guide 
• 60-day money-back guarantee.

Tips to Improve Your Performance on the McKinsey Problem Solving Game

Here are several specific tips to help improve your overall performance on the test as well as tips to avoid any disturbances that could hurt your score:

#1 Sharpen Your Mental Math Abilities

The ability to make fast and accurate calculations can help a lot in this Problem-Solving Game. That’s because one wrong calculation might ruin your carefully built Ecosystem or cause an invader to reach your Native Plant.

There are several free apps and sites, like the renowned Khan Academy , that can help you improve your math skills quickly.

#2 Learn Fast Reading Skills

Mckinsey’s PSG requires you to absorb and analyze a tremendous amount of information under strict time constraints.

Fast reading skills come in handy in this test and can help reduce the amount of time needed to understand the numerous guidelines of the mini-games.

There are certain apps and browser extensions that allow you to practice this important skill , even on the go.

#3 Focus Only on What Matters

Don't get nervous when you first see the immense amount of data on the mini-games. That’s because a lot of the data is irrelevant, and you’ll be only using some particular parameters .

For example, in the Ecosystem game, you’ll only have to use specific species and terrain specs for your calculations, while ignoring others that are there only for distraction.

In the complete   PSG Simulation Practice , you’ll see how to remove as much as 70% of the irrelevant data and remain just with the information that matters.

#4 Ignore Outside Information

While taking the assessment, especially the Ecosystem game, try to ignore any outside knowledge and information.

For example, if you’ve learned biology or zoology and you see that your food-eating rules don’t seem logical but the numbers are correct, always go with the numbers .

If you start to rely on previous knowledge, you might get confused and mess up your progress in the game.

#5 Learn to Solve Problems Like a Consultant

The PSG measures your consulting traits and compares them to a model McKinsey consultant.

That’s why learning to think and solve problems like a real consultant can help you pass this assessment.

Two main problem-solving skills you should practice are decision-making in fully controlled situations and with limited information.

Both of these skills can be trained using complex strategy games (examples are mentioned above) as well as  practicing with the   full PSG interactive simulation .

#6 Cut Down on Calculation Time Using Microsoft Excel

Mental math is an effective way to make calculations in the mini-games.

But as you’re only human, it’s not error-free. That’s why using a calculation tool, such as Excel formulas, can be a great way to make super fast and accurate calculations.

You can use it to gather all the relevant data, arrange it with columns and formulas (even in advance!), and turn the whole process into a no-brainer.

That said, you’ll need to use another monitor (preferably with a different browser) or another laptop since the assessment’s platform will take over your entire screen.

#7 Prep Your Hardware and Internet Connection

The last thing you want during the assessment is a “blue screen of death.”

It may happen if your hardware is not strong enough, since the McKinsey PSG is pretty demanding in its system requirements.

Any computer that is more than five years old or without an HD screen will likely encounter lags and performance drops.

Also, you must have a fast and stable internet connection. If you get disconnected in the middle of the test, you might need to start all over again or even reschedule for another testing date.

The PSG scores are divided into two types -

• Product score - the final outcome of your performance
• Process score - the efficiency (time and number of clicks) of your performance 

If you get the   PSG Practice Simulation , you’ll have a mock grading system that monitors your results and behavioral patterns.

This will allow you to track your progress while you practice for the test and see which areas demand improvement.

Why Did McKinsey Develop the Problem-Solving Game?

McKinsey created the Problem-Solving Game as an unbiased way to identify candidates from around the globe with strong cognitive abilities. The former assessment, Problem Solving Test (PST), was less challenging for candidates who were familiar with standardized tests, such as SAT and GMAT, or used the numerous mock tests found online.

The PSG, on the other hand, is supposedly crack-proof. That's because it takes into account the approach you use to solve the problems and not just the final solution. This seemingly removes any lucky guessing and shortcut techniques that were common on the McKinsey PST.

While on the PST you had just your final score, on the PSG your score is comprised of dozens of scoring criteria apart from your final result , including mouse movement, keystrokes, and clicks.

McKinsey can analyze these factors for every recorded candidate, which allows them to compare candidates more fairly.

What Does Imbellus Mean?

Imbellus is a company that creates immersive simulation-based assessments to assess cognitive processes. To develop a new testing format for the McKinsey recruitment process, they've teamed up with McKinsey consultants and UCLA Cresst psychologists.

In 2020,  Imbellus was purchased by Roblox , an online gaming platform, to help sharpen its recruitment practices.

This was an in-depth prep guide for the McKinsey Problem Solving Game. It gave you an overview of the different mini-games, explained their main challenges, and offered some useful solving tips.

Additionally, you saw the best ways to prepare for the assessment, when the PSG Practice Simulation being the most realistic and accurate one.

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• How to Beat the Games?
• Best Practice Options
• 7 Tips to Boost Your Performance