One of the main minigames in the McKinsey Solve game is the Ecosystem Building game (PSG). This means that it is one of the mini-games McKinsey candidates are most likely to encounter


This article will give you an overview of the Ecosystem Building game, the best methods to pass the game, and some suggested study aids.

A Brief Introduction to The Ecosystem Building Game

The Ecosystem Building game usually takes the scenario in a coral reef, on a mountain ridge or in the jungle. In this game, you are tasked with creating a stable marine or terrestrial ecosystem. To do this, you need to:

(i) choose a location that can support a variety of species

(ii) choose 8 particular animals to populate that location out of 39 given species. 


Each location and species have its own characteristics, which require different approaches. The ultimate goal of this game is a sustainable ecosystem, but not all of your species may survive. Your aim should be getting as close as possible to an optimal outcome, as this game tests your decision-making and systems thinking skills

It’s recommended that you spend 35 minutes, at most, on the Ecosystem Building game.

The Ecosystem Building Game’s Main Challenges

The difficulty of the Ecosystem Building game lies in the need to quickly absorb, calculate, evaluate and prioritize a massive amount of data. This includes the characteristics of 39 species (such as calorie intake, output, etc.), details of the terrain in each location (such as temperature, rainfall, etc.), and eating rules. 


To pass this game, candidates must meet all of those requirements. As mentioned, Ecosystem Building is, above all, a decision-making game. There are no ambiguities or false details because the game will give you all the information you need to make the right decisions. 

You may be distracted or tempted to make assumptions by some of the information, which is often irrelevant. There is no need for any prior knowledge of the environment, ecology, or biology is needed to succeed in this minigame, so don’t make any assumptions. Since this is the case, your results will depend heavily on your mental agility, specifically your ability to do quick calculations and filter out unnecessary information.

Best Strategies to Pass Ecosystem Building Game

There is no absolute guaranteed approach to any McKinsey minigames since everyone’s thinking process is different. However, candidates should greatly benefit from following these two guidelines: simplify the data and divide the process.

Simplify the data

Passing the Ecosystem Building game requires systematic data classification. The interface only lets you view a small number of data points simultaneously in addition to hundreds of unsorted statistical data. Rearranging and showing the entire dataset would help you deal with that massive amount of data.


The game could give you maybe 7-9 different factors for each animal and location, but not all of them are crucial. You should try to look for overarching patterns between the species and environmental factors. It is more important to find a rough but big-picture solution than to optimize one specific relationship. 

For example, if all species’ required living conditions include “wind speed” and “soil moisture,” understand that you only need to look at specific terrain characteristics when choosing the location to create a sustainable ecosystem.

Divide the process

You need to have a clear, logical plan of how you will proceed in the Ecosystem Building game. You should break your actions down into two more manageable steps, which are choosing the locations and constructing the food chain. Since they both support one another, you can perform either step first.


Dividing the process into separate steps would assist you in ensuring continuity in your food chain. There are two types of species in the 39 given species: producers (no calorie requirements) and consumers (consume either plants or other animals). You’ll have to choose which breeds of livestock and food producers to include in your herd. Use the top-down or bottom-up strategy to arrange the: 

  • Working your way down the food chain, you can start with the apex predators (species that are not eaten by any other species).
  • Working your way up, you can start with the primary producers (who do not consume any other species).

Resources to Practice Ecosystem Building Game

Note-taking templates and PSG simulations are the most effective study aids for the Ecosystem Building game.


Excel is the most versatile interface for data organization when taking notes. There are many templates already designed for the Ecosystem Building game on the Internet. However, if you want a more customized note-taking experience, you can make one suited for your thinking process. If you like taking notes on paper, you can print them out.

The ability to master an unfamiliar and challenging game like Ecosystem Building requires prior practice. PSG simulations are the best resource for practicing the Ecosystem Building game. They can offer you the chance to participate in actual games and an endless number of opportunities to hone your abilities.

That was everything you need to know about McKinsey Solve’s Ecosystem Building game. If you want to find out more, experience the game yourself!