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McKinsey Problem Solving Game: the ultimate guide

By Max Serrano on July 23, 2020 How we wrote this article
McKinsey Problem Solving Game

McKinsey's Problem Solving Game (PSG), also known as the Imbellus test or Digital Assessment, is a virtual "test" used to evaluate McKinsey candidates during the application process.

McKinsey says that no specific preparation is needed for the new assessment. However, in our experience you can (and should) prepare for the test. In the guide below we've compiled key information about the McKinsey Problem Solving Game and some tips to help you get ready. Let's get started!

Click here to practise 1-on-1 with McKinsey ex-interviewers

1. Background

1.1 What is the McKinsey Problem Solving Game (PSG)?

Let's start high-level. The McKinsey Problem Solving Game is an assessment that the firm is using in order to evaluate their applicants during the early stages of the interview process. 

If you're familiar with the McKinsey PST (Problem Solving Test), then it will be helpful to know that the Problem Solving Game is intended to serve a similar function (i.e. screen candidates early in the process) but in a very different way.

McKinsey's Problem Solving Game is really the first assessment of it's kind in the consulting industry. For a brief overview of the assessment that comes straight from McKinsey, check out this video.


1.2 Purpose

At the end of the day, McKinsey's business is dependent on hiring exceptional problem-solvers to serve their clients. The purpose of the Problem Solving Game is to help McKinsey do a better job of finding the best talent among their vast pool of annual applicants. 

Now, to be more specific, the Problem Solving Game is intended to help the firm do a few things in particular:

  • Hire the candidates who will perform best on-the-job, not just the candidates who can do well on a test
  • Evaluate the thought process of candidates, rather than just their final answers
  • Increase diversity by reducing the biases of other methods of standardised testing (like the McKinsey PST)

McKinsey's global director of people analytics and measurement, Keith McNulty, alluded to the above priorities when he made this comment about standardised multiple-choice tests:

"[T]here’s a large amount of strategy, preparation, and luck involved in multiple-choice tests, and if you use them in the selection process, it reinforces the status quo—at a time when you are looking to widen the scope of candidates you’re hiring.”

1.3 Imbellus (acquired by Roblox)

The McKinsey Problem Solving Game was not built in-house by the firm. Instead, they worked directly with a start-up called Imbellus, in order to develop the assessment. In 2020 Imbellus was acquired by Roblox but McKinsey has continued using the digital assessment.

The core idea of the Problem Solving Game is to evaluate how people think, not just what they know. McKinsey believes that standardised testing is a poor predictor of real-world performance, and so they aim to evaluate candidates in a more robust and less biased way with this test.

1.4 Pilot and roll-out

The Problem Solving Game was tested with an initial group of 527 McKinsey candidates at the London office in November of 2017. Then in late 2018, the test was given to additional candidates from additional McKinsey offices. During these tests, the assessment could only be given on McKinsey-owned computers at a local McKinsey office. 

But then, a new version of the assessment was developed that allowed it to be taken online. The online version of the assessment was rolled out in late 2019, and as of the writing of this article, the Problem Solving Game has been played by over 15,000 people in at least 30 countries. 

Today McKinsey uses the PSG as its default initial assessment in the interview process.

2. Game structure

Now let's dig into more details about the Problem Solving Game and what you can expect on the assessment. Let's start with an overview.

2.1  Overview

Here is a brief summary of the way the PSG is structured:

  • A computer-based assessment
  • An experience similar to a video game
  • About 70 minutes of total run time
  • 2 scenarios
  • 2-4 tasks within each scenario

Although the above elements are fairly consistent, the game is actually different for every candidate.

2.2 Different for every player

When you are invited to take the PSG, you will be given a unique link which will allow you to do three things:

  1. Run a tech diagnostic programme to ensure your computer and network meet the requirements needed to complete the assessment
  2. Schedule a specific time slot for you to take the assessment
  3. Take the assessment during your scheduled time slot

Here's where it gets interesting. When you begin the assessment during your scheduled time slot, the system will load a unique version of the game just for you. That means that the iteration of the game that you face will be different than every past or future iteration of the game.

With that said, all versions of the game contain something called "scenarios". 

2.3 Scenarios

The assessment is divided into two primary components: scenarios and tasks. A scenario is the digital world and situation where you find yourself. Each scenario has an over-arching objective and contains several tasks, which are smaller "bite-sized" objectives. When you take the Problem Solving Game, you should expect to face 2 different scenarios.

One is called Ecosystem, and the other Redrock. These are the only two scenarios currently being used. There are other scenarios which you might have heard of (Plant protection, Disaster management, Disease management, Migration management) but these aren't used anymore.

So to summarize, as of writing this article, here is what you need to know about the scenarios:

  1. Ecosystem creation - Currently used
  2. Redrock study - Currently used
  3. Plant protection - Not used anymore
  4. Disater management - Not used anymore
  5. Disease management - Not used anymore
  6. Migration management - Not used anymore

Let's dig deeper into the two scenarios currently being used.

Ecosystem management

The McKinsey Ecosystem game is a crucial part of McKinsey's recruitment process. In this game, candidates are tasked with creating a sustainable ecosystem on an island and selecting an appropriate location for it, all within a strict 35-minute time limit. To succeed, candidates must choose 8 species out of a pool of 13, considering factors such as whether they are producers or animals and their environmental requirements.

The game challenges candidates to create a balanced food chain within the chosen environment, ensuring that each species receives enough calories from its food source. To simplify the process, an Excel Solver tool is available to quickly identify if a selection can lead to a sustainable chain. This tool can be a valuable resource during the game.

Ultimately, the Ecosystem game assesses candidates' ability to make rapid and strategic decisions under pressure, demonstrating their problem-solving skills in creating a sustainable ecosystem.

Redrock study

The Redrock is a new addition to the McKinsey game, introduced in 2022 in the United States and replacing the previous second game, Imbellus – Plant Defense, as of February '23. This change brought a different format to the Problem Solving Game (PSG), focusing more on calculations, especially percentages, similar to the older McKinsey PSTs.

In the Redrock game, players are sent to an island to analyze the population of animals, specifically wolves and elks, and make predictions based on the data. The game consists of four phases: Investigation, Analysis, Report, and Cases, with a total time limit of 35 minutes, including short breaks before each phase.

The Investigation Phase involves gathering information from provided text, graphs, and tables, which can be used in later phases. The Analysis Phase requires answering math questions related to different animal groups, with access to a calculator and the Research Journal. The Report Phase includes both written and visual components, where you answer questions and choose a graph to represent analysis results. Lastly, the Cases Phase, introduced in 2023, involves answering up to 10 unrelated questions, typically taking around 2 minutes each.

Overall, the Redrock game represents a significant shift in the McKinsey recruitment process, focusing on analytical skills and calculations, and it may be challenging for candidates to complete within the time limit.


3. Skills tested

McKinsey is using the Problem Solving Game for a reason. They want to make sure that the candidates they hire, have what it takes to succeed on the job as consultants. 

So, what exactly is McKinsey evaluating when you play the game? You could call them skills, but skills isn't quite the right term to use here. This abstract describes the areas upon which candidates are assessed during the PSG as "cognitive constructs".

This makes it sound complicated, but you can simply think of these "cognitive constructs" as the areas of your thinking that McKinsey wants to measure. There are 5 of these areas, and we've covered them in more detail below:

3.1 Critical thinking

As you may be aware, consultancies (and other employers) place a high value on their candidates' critical thinking abilities. Just so we're working off of the same definition, here is how Stanford defines critical thinking: "critical thinking is careful goal-directed thinking".

When a consultant begins on a project, they will typically have (or form) a set of objectives that the client wants to accomplish. At the same time, they will likely encounter competing priorities and a combination of relevant and irrelevant data.

The best consultants will have a knack for focusing on objectives, and systematically identifying the most relevant information to form an approach and recommendation. That's why critical thinking is one of the primary areas that McKinsey wants to evaluate with the assessment.

3.2 Decision making

The Problem Solving Game also evaluates your decision making. And one of the elements of the test that distinguishes it from more traditional standardised tests is that it evaluates both your end result and HOW you came to that decision. Whereas a multiple-choice test (like the McKinsey PST) is only capable of assessing candidates based on their end results.

For example, as you progress through a scenario within the Problem Solving Game, you'll gather information, do some analysis, and then take action to implement your approach. During each interaction you have with the game, the software is gathering data. It's measuring details like the amount of time you spend on each task, what information you are looking at onscreen, as well as the actions you ultimately take.

In the real world, McKinsey would rather have candidates who can make decisions strategically, even if they are wrong occasionally, rather than candidates who are good at guessing on standardised tests. Some people can do both, but you get the point.

3.3 Metacognition

Candidates are also evaluated on their metacognition. As described by Nancy Chick of Vanderbilt University, metacognition can be summarised as "thinking about one's thinking". 

You could also characterise metacognition as a person's ability to take a step back and recognise their own understanding and knowledge gaps for a particular topic. 

Having strong metacognition can make a significant difference in a person's ability to learn and adapt to new situations. McKinsey consultants often work on complex projects, and it's important for the firm to hire people that can learn quickly and excel in changing circumstances.

3.4 Situational awareness

When a candidate interacts with the scenarios within the PSG, their situational awareness is also put to the test. Situational awareness is a person's ability to understand their environment as well as it's likely future outcomes. To illustrate this point, situational awareness is an important ability for firefighters.

Imagine a home catches on fire and the fire department is called. When they arrive on the scene, the firefighters need to quickly assess the situation and understand key pieces of information (e.g. are any people inside? Where are the nearest fire hydrants? Etc.). At the same time, the firefighters will also understand the likely future outcomes of a particular fire, and they can use this insight to help them prepare their approach for extinguishing the flames.

In a similar way, McKinsey wants to hire candidates who are able to understand the key elements of a new situation, anticipate the likely outcomes, and use their situational awareness to prepare a strategic approach.

3.5 Systems thinking

Finally, the Problem Solving Game is meant to test candidates' systems thinking. Systems thinking is a person's ability to understand and work with the complexities of an interconnected system. To test this ability, the Imbellus test uses the natural world, which provides some excellent examples of complex systems. 

For example, a coral reef is a system with a variety of interdependent parts, including plants, animals, water, the water temperature, and more. If you change one element of the system, it can impact the system as a whole.

Likewise, the clients that McKinsey serves are deeply impacted by systems (e.g. the global economy, data processing, and more). As a result, hiring candidates that can understand and work within a systems-context, will be an advantage for McKinsey.

4. How to prepare

Now let's talk about beating the game. 

First, we want to remind you that every candidate who plays the Problem Solving Game is encountering a completely unique game. You can't memorise a set pattern or sequence that will consistently get you a high score.

Also, remember that the game is measuring HOW you approach the problem and not just your outcomes. So, even if you have good results, if you got there using a strange or illogical approach, that could pull down your overall score.

Due to these factors, you can't prepare for McKinsey's Problem Solving Game in the same way that you would prepare for other tests (like the PST). In fact, according to McKinsey you DON'T even need the following for the Problem Solving Game:

  • Any specific preparation
  • Experience with video games
  • Specific business knowledge

That's what they say, but if you have the opportunity to interview with McKinsey, we know that you'll want to be as prepared as possible! So, we've compiled the below tips, which we recommend you use to get ready for the assessment.

 4.1 Play video games, seriously

Even though no video game experience is required to play the Problem Solving Game, it was designed (at least in part) by game designers. And if you play the right kind of video games, there are elements of the strategy and mechanics that will be similar to what you may encounter on McKinsey's assessment.

We recommend that you specifically play two types of video games to help you prepare: 

  1. A "world builder" simulation game like SimCity
  2. A "tower defense" game like Kingdom Rush

To be clear, the graphics and experience of the games above will likely look quite different than what you'll find within the Problem Solving Game. BUT, by playing games like these, you'll pick up helpful strategies and a better understanding of the game mechanics and flow. 

We would also recommend that you practise these video games on the same device that you would use to take the Problem Solving Game (likely your primary laptop or desktop computer). That way you will be replicating the style of play as closely as possible.

The two games we've mentioned above are most closely aligned with the ecosystem creation and plant protection scenarios of the Problem Solving Game that we mentioned in section two of this article.

Similar to the ecosystem creation scenario on the Problem Solving Game, in SimCity you have to build a system (in this case a city) with a variety of interdependent parts. And in both games, you have to achieve a level of balance between different parts of the system. 

Similar to the plant protection scenario on the Problem Solving Game, in Kingdom Rush, you have a variety of elements that you can build to slow or stop invaders. And although the elements that you'll have will be different (e.g. predators vs. archers) the basic strategies involved in most tower defense games are similar.

Now, as you may have already noticed, these games are useful for two of the scenarios we mentioned in section two above. For the other scenarios, we have not found any video game that is clearly relevant. So, for those scenarios, you'll need to rely more on the other preparation steps below.

4.2 Study the known scenarios

As we mentioned previously, there are four publicly known scenarios that have been used on the Problem Solving Game. As a recap, here's what they are:

  • Ecosystem creation
  • Plant protection
  • Disease management
  • Disaster management

We'd encourage you to carefully review the information that we've summarised for each scenario in section two of this article. This will help you to start getting comfortable with the situations you'll encounter (note: McKinsey could add new scenarios not listed above).

As you learn the basic details of each scenario, you could also outline potential strategies for each one, as a mental exercise.

For example, in disease management, you'll need to identify the disease you're dealing with, and then take action to contain and treat it. Until you play the PSG, you won't have all the data, but you do know the basic objective of the game. So, make-up a hypothetical disease situation, and then outline a few potential strategies that you could take to help local wildlife.

A mental exercise like this obviously won't match the exact way the Problem Solving Game operates. However, it will get you to start thinking strategically, within the context of the specific scenarios that you will face. This alone will likely make you feel more confident when you take the assessment, and you may find that some of your ideas will come in handy on game day.


4.3 Prepare your workstation

This is a bit more logistical, but it's very important.

The McKinsey Problem Solving Game is somewhat demanding from a hardware perspective. You'll need a computer that runs pretty quickly and has at least 8GB of RAM. If you have an old or slow computer, then we would recommend that you either borrow or purchase a new one prior to taking the test. 

You'll also want to make sure you have a fast and stable internet connection before taking the assessment. If your wifi is spotty, you could try connecting to the internet through a direct ethernet connection. Or, you could ask a friend or relative with a good connection if you can take the assessment at their place.

Prior to taking the test, you will need to run McKinsey's "tech diagnostic" to ensure you have the processing power to run the Problem Solving Game. When McKinsey invites you to take the assessment, they'll send you more details on how to access this tech test. 

As much as possible, you'll also want to carve out a time and space to take the assessment with no distractions. It's important to plan this in advance, and it also helps if you can do your preparation in the same environment.

4.4 Start practicing case interviews

The McKinsey Problem Solving Game is very different than a case interview. However, if you get good at solving case interviews, some of those skills will also be helpful on the Problem Solving Game. 

For example, in the game, you'll need to develop a strategy with incomplete or inconclusive information. You also have to do this when you're solving a case interview. 

This is also a great strategy because it will help you get a head start on your preparation for the case interviews that you'll encounter later in the McKinsey interview process.

After getting some practice on your own, you should find someone who can do a mock interview with you, such as a friend or family member.

We’d also recommend that you do mock interviews with ex-interviewers from McKinsey. This is the best way to replicate the conditions of a real interview, and to get feedback from someone who understands the process extremely well. You may not have the connections to do this on your own, but we’ve made the connections for you. Book your McKinsey mock interview now.


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