McKinsey Problem Solving Game: Full Practice Guide 2023


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In the recruitment process of McKinsey, a renowned consulting firm, the McKinsey Problem Solving Game (PSG) has become a crucial assessment tool. This gamified test, also known as McKinsey Imbellus, McKinsey Digital Assessment, and Solve, has replaced the previous assessment called the Problem Solving Test (PST). This comprehensive guide will provide you with a complete understanding of the PSG and offer tips on how to excel in the assessment.

Understanding the PSG Format

The McKinsey PSG is typically sent to candidates once they successfully pass the initial resume screening, making it the second stage in the hiring process. Candidates participating in the McKinsey PSG are typically required to solve two out of these six mini-games within a total time of 71 minutes, including the time needed to read the instructions. The game not only evaluates your problem-solving abilities but also your time management skills and ability to perform under time constraints.

  1. Ecosystem Building: Construct a sustainable ecosystem within a defined area, considering various factors such as species interactions, resource availability, and environmental sustainability.
  2. Plant Defense: Protect a rare plant using predators to defend it against animals. Test your understanding of ecological dynamics and strategic decision-making.
  3. Redrock Study: Analyze data, extract insights, and visually present them to address business concerns. Assess analytical skills and effective communication.
  4. Disaster Management: Recognize and take prompt action to protect ecosystems from natural disasters. Minimize damage through quick thinking and effective decision-making.
  5. Disease Management: Analyze data, identify patterns, and implement strategies to control and manage disease outbreaks within ecosystems.
  6. Migration Management: Guide animals on a successful migration, minimizing losses by navigating obstacles and making optimal decisions.

As of March 2023, reports suggest the Disease, Disaster, and Migration mini-games have become extremely rare, potentially phased out from the PSG. The remaining mini-games continue to assess problem-solving abilities and suitability for consulting roles.

Scoring Criteria of the McKinsey Problem Solving Game (PSG)

To assess candidates’ problem-solving abilities effectively, the McKinsey Problem Solving Game (PSG) incorporates a comprehensive scoring system that evaluates two key dimensions:

1. Product Score: Evaluating the Quality of the Outcome

The Product Score measures the quality of candidates’ outcomes in the PSG. It assesses if candidates successfully “win” the games by creating a sustainable ecosystem and protecting the plant. This score reflects the overall success of candidates’ solutions, indicating their ability to provide effective resolutions to complex problems.

2. Process Score: Assessing the Approach to Reaching the Outcome

The Process Score evaluates candidates’ approach to achieving the desired outcome in the PSG. It considers every click made by candidates and other variables to understand their decision-making process. Factors like nervousness and execution of a rational plan are taken into account.

By analyzing the Product Score and Process Score, McKinsey gains insights into candidates’ problem-solving abilities, creativity, adaptability, and analytical thinking. These scores help assess candidates’ suitability for consulting roles, where exceptional problem-solving skills are vital.

Essential Skills Assessment

The McKinsey PSG evaluates candidates’ qualifications and consulting traits, comparing them to those of actual consultants. It measures five key thinking skills:

  1. Critical Thinking: Analyzing complex situations and developing logical solutions.
  2. Decision-Making: Efficiently processing information and making informed choices under time constraints.
  3. Meta Cognition: Monitoring and improving cognitive processes through self-awareness.
  4. Situational Awareness: Managing multiple tasks, prioritizing effectively, and time management.
  5. Systems Thinking: Understanding interconnected elements and identifying root causes within a broader context.

By assessing these essential skills, the PSG helps identify candidates who possess the necessary competencies to thrive in the demanding world of consulting.

A Comprehensive Breakdown of the Mini-Games in the McKinsey Problem-solving Game

To date, candidates have reported six different scenarios in the McKinsey Problem-Solving Game (PSG). Recent reports from March 2023 indicate that the Disease, Disaster, and Migration mini-games have become exceptionally rare, possibly indicating their gradual removal from the PSG. This breakdown focuses on the three most commonly seen scenarios: Ecosystem Building, Plant Defense and Redrock Study. It also covers Disaster Management, Disease Management, and Migration Management. Strategies and steps are provided for each mini-game to enhance performance.

Ecosystem Building (Most Common)

Objective: Build a self-sustaining natural ecosystem in a coral reef or mountain range.

In this mini-game, you are provided with various animals and plants, each with different nutrient requirements and living conditions. Your task is to select the optimal combination of species and location to create a sustainable ecosystem. Building a food chain of 8 species is necessary to succeed.

Step 1: Select the location

  • Utilize a spreadsheet or scratch paper to list the terrain specifications and calorie provided by the producers in the mini-game.
  • Identify the changing terrain specifications and focus on them as relevant factors for decision-making.
  • Calculate the sum of calories provided by the producers in each layer and determine the layer with the highest calorie provision, indicating the easiest chain to build.

Step 2: Build the food chain

  • List the consumers with compatible terrain requirements in a spreadsheet.
  • Start building the food chain from the apex predator with the lowest calorie requirement, following a top-down approach similar to an issue tree.
  • Aim for a food chain with 3-4 levels and a total of 8 species.
  • Alternatively, use a bottom-up approach by examining the “Eaten By” specifications of each species until reaching the top predators.

Step 3: Triple-check and adjust

  • Ensure each species in the food chain is compatible with the chosen location.
  • Verify the continuity of the food chain and check if each species is supplied with enough calories without being eaten into extinction.
  • Adjust the food chain if any of the checks are not met.

Plant Defense

Objective: Protect an endangered plant from incoming invaders.

In this tower-defense-style mini-game, invaders move through a grid, and you must use limited defenders and terrain to prevent them from reaching the plant.

Step 1: Understand the rules and plan your defense

  • Carefully read and understand the rules of the game. Pay attention to the types of defenders and barriers available, as well as any special features or limitations.
  • Familiarize yourself with different invader types, their movement patterns, and strengths/weaknesses.
  • Analyze the grid and invaders’ paths, identifying strategic locations and chokepoints for defenders and barriers to maximize their effectiveness.

Step 2: Execute defense strategy

  • Consider the types of defenders and barriers at your disposal. Each has unique abilities and limitations. Think about how they can be strategically deployed to block the invaders effectively.
  • Plan your defense strategy by deciding where to place defenders and barriers to create obstacles for the invaders. Take into account the movement patterns and strengths of different invaders.

Step 3: Optimize your defense and adapt

  • Evaluate defense effectiveness and make adjustments as waves progress.
  • Prioritize defenders effective against specific invader types.
    Adapt defense strategy to new invaders and changes in their behavior.

Redrock Study

Objective: Extract information from text, graphs, and tables to answer numerical questions.

This mini-game requires you to play the role of a researcher. You will collect relevant data points from articles, graphs, and tables and use them to answer three quantitative questions. Pay attention to the research process, including investigation, analysis, and reporting stages. Be aware that the format may vary, with phase 2 potentially including additional standalone questions.

Step 1: Investigate and gather relevant data

  • Carefully read the research objective provided at the beginning of the game. Understand the specific information you need to extract.
  • Analyze the text paragraphs, graphs, and tables presented. Identify the key data points and details that are relevant to your research objective.
  • Drag and drop the selected information into your research journal. Organize it in a logical manner for easy reference.

Step 2: Analyze and answer numerical questions

  • Use the collected data to calculate the answers.
  • Take advantage of the virtual calculator provided in the game to perform necessary calculations.
  • If the data in your research journal is inadequate to answer a question, refer back to the article and extract any additional relevant information needed.
  • Utilize your chart reading, percentage calculation, and data interpretation skills to solve the numerical questions effectively.

Step 3: Summarize and visualize data

  • Create a summary based on collected data and answers.
  • Visualize data using suitable graphs.
  • Present findings clearly and accurately.


The McKinsey Problem Solving Game offers a stimulating and immersive experience for individuals aspiring to excel in the consulting industry. By understanding the structure of the game, focusing on key strategies, and practicing problem-solving skills, you can enhance your performance and stand out in consulting case interviews. 

Remember, success in the game requires a combination of critical thinking, strategic planning, and adaptability. So, dive in, explore the intricacies of each mini-game, and unlock your full potential as a problem solver in the world of consulting.

Now, get ready to tackle the McKinsey Problem Solving Game head-on and embark on an exciting journey of discovery and growth.

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