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This question is read-only because it has been merged with Has anyone tried the new McKinsey Imbellus Problem Solving Game? Any tips / lessons learnt?.

Does Anyone know more about the new Mckinsey test "Imbellus" which is replacing PST? Anyone who took this exam? Tips?Tks

Imbellus McKinsey McKinsey Imbellus PST
New answer on Sep 18, 2020
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Andrew asked on Apr 09, 2019
Actively preparing for case interviews at Bain&Co., McKinsey, BCG.

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Content Creator
replied on Jun 07, 2020
Ex-McKinsey EM | Experienced interview coach (1,000+ sessions) | Discount on 1st session | LBS MBA

Hi Andrew,

McKinsey Digital Assessment is based on a game developed by an American start-up Imbellus that uses Artificial Intelligence to place candidates in a range of lifelike scenarios and assess their decision-making skills and cognitive processes. Thus far it has been only deployed at McKinsey, but rest assured that other top tier consultancies will be quick to follow with a digital game-based assessment of their own.

McKinsey Imbellus Test

Imbellus’ psychologists designed the game to evaluate candidates across five cognitive abilities:

  • Critical thinking: forming a judgment based on a set of data
  • Decision making: selecting the best course of action under time constraints
  • Meta-cognition: planning and monitoring own learning and performance
  • Situational awareness: forecasting outcomes based on the relationship between multiple variables
  • Systems thinking: understanding cause and effect relationships

McKinsey says that the game tracks every move of the mouse, hesitation, and time spent on every action. It then uses data science to score the candidate across the five abilities.

How does it work?

The assessment consists of two scenarios, each taking approximately 30 minutes, with the second scenario broken into three parts. While the time limits are recommended, it has been reported that candidates who spend more time in the first scenario, have less time for the second one.

1. Ecosystem Management: candidates are expected to create a sustainable ecosystem either on a mountain ridge or a coral reef. The first step is to select the best location based on a range of attributes, such as wind speed, pH of the soil, and temperature; next choose 8 species of animals and plants from a selection of 40 based on a range of characteristics, such as number of calories needed to survive and ideal environment.

The most complex part is matching the animals to each other by calculating the number of calories they need to consume vs the number of calories they offer when consumed. Working down the food chain, starting from the predators can simplify the task.

McKinsey Imbellus Problem Solving Test Example

2. Protect the Plant: candidates need to protect a plant from invading species through six rounds of play, using the provided tools, such as predators and terrain barriers, to stop or slow them down.

One of the challenges is deploying the majority of tools before knowing where the invasion will start or what the effect of the measures will be on the invaders. The key is to experiment, carefully record the results, and leverage the learnings in subsequent rounds.

How to succeed?

No-one really knows how to “win” in the game just yet, but one thing not to do, is to try and replicate the actions of someone who has taken the assessment before. The game has enough variability to prevent any attempt of cheating. Every user sees a unique version of the scenarios.

It is especially important to read the instructions carefully and take the time in the tutorials. There are a lot of details that can feel overwhelming. Think 80/20 and get comfortable with making decisions in conditions of ambiguity, and partial information, while always rooting the decisions in the facts.

How to prepare?

One of the reasons for switching to Imbellus is that candidates can prepare for the PST. Multiple previous and mock tests available online can get you in order for the old 1 hour, 26 questions test. McKinsey found a strong bias towards applicants with the time and resources to purchase mock tests and practice for the PST.

The Digital Assessment is meant to be a novel scenario for applicants, which is still evolving and changing between recruitment cycles. In theory, the game should prevent candidates with exact sciences background from having an advantage. Instead, it tests logic, decision-making, and clarity of thought.

If you are into video games, you are in luck! If not, it might be a time to start. Candidates report that the Imbellus assessment reminds them of the popular category of “tower defence” games, in particular, Kingdom Rush and Planet Zoo. Worst case, this is another, potentially useful way to spend time during the quarantine.

Get in touch if you would like to discuss further.

Anonymous replied on May 16, 2020


Whilst you don't have to be a gamer to perform well, the game will certainly test your problem solving ability and your ability to navigate in challenging circumstances.

Which skills are tested?

The game records all of the candidate’s actions (e.g., every movement of the mouse, time spent to choose an action) and uses machine learning to assess candidates’ way of thinking. It’s as much about how close candidates come to the best solution as about how they tackle the problem through. During the game McK assesses 5 cognitive abilities that are critical for a career in consulting:

  • Critical thinking: the ability analyze information objectively and make a reasoned judgment
  • Decision making: the ability to select the best course of action among several options
  • Self-awareness: the ability to self-assess
  • Situational awareness: the ability to be fully aware of your surroundings at all times, allowing you to react effectively
  • Systematic thinking: the ability to understand different parts of a system and how they work together through cause/ effect relationships

How to cultivate these skills?

Let’s break down each skillset and find ways to improve.

Critical thinking could be broken down into the following subskills:

  • Think about a topic in an objective and critical way
  • Identify the connections between ideas and working out whether the evidence provided supports those ideas or not
  • Evaluate a point of view to determine how strong or valid it is
  • Recognize any weaknesses that there are in the evidence or argument
  • Notice what implications there might be behind a statement
  • Provide structured reasoning and support for an argument that we wish to make

In order to improve your critical thinking I would suggest using mind mapping technique. It exploits the fact that our brains process information visually much more effectively than they do when it’s presented in a written document.

The idea behind mind mapping is that you start with a central theme or idea, typically drawn in a box in the middle of the page, and then from that you create branches, which lead to other ideas, or to supporting evidence or ancillary information.

Decision making could be broken down into the following subskills:

  • Establishing a positive decision-making environment
  • Generating potential solutions
  • Evaluating the solutions
  • Deciding
  • Checking the decision

In order to improve your decision making skills I would suggest that you start applying it to your everyday life situations and start developing small decision making frameworks for each situation (e.g. going to the shop)

Self-awareness could be broken down into the following subskills:

  • Monitor Your Performance
  • Seek Out Feedback and Then Use It

The best way to improve your self-awareness is to reduce your EGO barrier and blind spots. You can read Ray Dalio Principles for more details.

Situational awareness could be broken down into the following subskills:

  • Identifying the baseline for the situation you are in
  • Recognizing any variations to the baseline

In order to improve your situational awareness I suggest that you take typical life situation and:

  • Monitor the Baseline. At first, this will require concentration effort. But after a while, you will find that you can monitor the baseline subconsciously
  • Fight Normalcy Bias. This requires you to be paranoid for a while as you develop your skill. Look at every disturbance to the baseline - this will allow you to stop ignoring or discounting any factors

Systematic thinking could be broken down into the following subskills:

  • Identifying all the elements in the system
  • Understanding the correlations between the elements

This skill could be largely improved by solving business cases.

ALSO I suggest that you should start investing your time into playing different computer/mobile game, where you can practice applying these skills.

Hope it helps!


Content Creator
replied on Apr 11, 2019
#1 rated Bain Coach | 10y+ coaching candidates to secure offers at MBB | Personalized preparation | MBA / Expert tracks

It is a time-pressured gamified-environment test. Candidates are allotted 60 minutes, the recommended amount of time excluding cases of learner accommodation, to complete the three scenarios. It is done on laptop in a controlled environment.
Multiple scenarions have been developed by Imbellus, but the one i have been hearing about is a simulated world where there are species of animals and plants are dying to an unknown illness and you need to you to figure out what to do in order to protect them.

Here (just for fun reading) I shared the paper of the pilot test results they have done within McK:

Evaluation of your score will be done on these codified criteria:
1) Critical Thinking
2) Decision Making
3) Metacognition
4) Situational Awareness
5)Systems Thinking

No specific preparation needed. As general tips:
- Have a good sleep before the test
- Keep an eye on time


Andrew on May 07, 2019

Thank you Riccardo!

Anonymous replied on May 05, 2020

Dear Andrew,

It's gamplified test for 1 hour long. And the thing is that there is no way to prepare for it. But here are some tips, you can follow:

  1. Focus on the process
  2. Follow time tracking. It is easy to get lost in the details and the sheer complexity of information overload the test presents.
  3. Look into the key skills that are being assessed by Imbellus and if you find any weaknesses - then work on them in advance.
  4. Get ready to make 80/20 decisions based on incomplete information. Likely you won’t reach the best answer within 60 minutes, however, you should reach a good answer, demonstrating a clever problem-solving strategy along the way.
  5. Take notes of your observations on the mechanics of each scenario so that you can analyze it.
  6. Get comfortable to calculate with pen and paper math.
  7. Enjoy

Hope it helps,


Content Creator
replied on Sep 18, 2020
#1 Coach for Sessions (4.000+) | 1.500+ 5-Star Reviews | Proven Success (➡ | Ex BCG | 10Y+ Coaching

Hi Andrew,

This is probably too late for you, but hopefully useful for someone else.

I did an in-depth study on the Imbellus. Most of the comments I found online are something like this:

  • You cannot prepare – it tests who you are
  • Play a lot of videogames
  • Don’t waste time
  • Be yourself
  • Be 80-20
  • Take notes well
  • Enjoy yourself

Not sure what you think, but I don’t believe that’s very useful. Nor did the several people I coached who had to do the test.

So I worked hard with the candidates that actually did the test and created a guide with everything you need to know on the Imbellus.

This guide will:

  • Show you the perfect strategy for each of the 4 Game Scenarios
  • Explain every single part of the Game with ad-hoc pictures
  • Detail the exact steps to improve in the 5 Skills tested in the game
  • Provide you insider information from previous applicants who succeeded in the game
  • Reveal the must-know answers to the most common questions on the Imbellus
  • Offer you a ready-to-use Excel template to maximize results in Scenario 1 with a detailed tutorial
  • Give you a proven template to build the food chain in Scenario 1

This guide will cover every single part of the Game, so you can be 100% confident the day of the assessment, without worrying “I should have prepared better for this”. You won’t need any additional material to prepare after it.

You can download the guide instantly here:

McKinsey Imbellus Test Guide

As an extra bonus, I am offering for a limited time the Consulting Industry Cheat Sheet (worth $29) for free with the guide. You will get access to key insights of the 17 most common industries in case interviews.

If you need additional support or have any questions on the guide please feel free to PM me, I am happy to provide extra tips for free.



Anonymous C replied on Apr 10, 2019

Not much to study. They will test you in a way which is hard to prepare for. If you have the chops you´ll be fine. If you dont its probably for the best!

Then get to stressed out about it.

Ben gave the best answer


Content Creator
Ex-McKinsey EM | Experienced interview coach (1,000+ sessions) | Discount on 1st session | LBS MBA
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