Learn the case interview basics, practice with 200+ cases, and benefit from extensive test materials, and interactive self-study tools.
Topic Overview
Topic Overview
Interview First Aid
Get ready for your case interview with our Starter's Guide to Case Interview Prep. Learn everything you need to crack the case and start a career in consulting.
How to Start The Case Interview Preparation
Conduct Mock Interviews with Peers and Coaches
Find out how to crack any case in your consulting job interview with our Case Interview Basics. We help you to get ready for a career as top consultant!
Preparation for Case Studies
Approaching a Case
Interviewer- vs. Candidate-Led Cases
Note-taking in Case Interviews
You want to ace the personal fit interview? We got what you need to display your personality. Start your consulting career with our Case Interview Basics!
The Personal Fit Interview
Key Questions in the Personal Fit Interview
The STAR Method
Get ready for online assessments such as the McKinsey Imbellus Game, BCG Online Case or Bain Sova Test during your interview in consulting.
BCG Online Case
McKinsey Imbellus Game
Bain Sova Test
Pymetrics Game Assessment
Case Cracking
Identifying your case type is the first and most crucial step to ace your case interview. Learn how to crack consulting cases with our Case Interview Basics.
Market Sizing
Market Entry
Profitability Cases
Growth Strategy
M&A Cases
Competitive Response
Pricing
Valuation
Brainteaser
Use the best consulting techniques to structure your thoughts and ace your case interview. Learn how to crack consulting cases in our Case Interview Basics
Issue Tree
MECE Principle
Pyramid Principle
Porter's Five Forces
4C Framework
4P Framework
2x2 Matrices and the BCG Matrix
The Stacey Matrix
Influence Model
ADKAR Model
McKinsey Growth Pyramid
Practice the basics like math skills and reading data charts to ace your case interview. Learn how to crack cases in our Case Interview Basics!
Charts and Data in Case Interviews
Why Math Matters
Math Skills Required in Case Interviews
Fast Math
Important Facts
Correlation and Causality
Qualitative and Quantitative Analysis
ROI and ROAS
Business Concepts
Back to overview

The Stacey Matrix

The Stacey Matrix is an important tool in project management that was invented by Ralph Douglas Stacey in the 1990s.

In this article, we will explain the Stacey Matrix, provide examples of project types, discuss its use in case interviews and consulting, and conclude with its pros and cons in project management. Enjoy your read!

What Is the Stacey Matrix?

The Stacey Matrix is a tool for representing and managing complexity in projects. It helps teams navigate uncertainty and align on the most suitable approach for project execution. It consists of two axes: Requirements (y-axis) and Approach (x-axis). Requirements represent β€œwhat” needs to be developed, while the Approach represents the 'how'. It is commonly used in software development and IT consulting to determine the complexity of a project or task. πŸš€

Within the axes, there are four areas:

  1. Simple
  2. Complicated
  3. Complex
  4. Chaotic

The character of a project is defined along its bisecting line. Closer proximity to the axes' intersection denotes simplicity, with clear goals and established approaches. Moving away leads to increasingly complex areas, culminating in ambiguity where goals and approaches are entirely unknown. In the IT sector, this scenario is commonly termed "agile," relying on agile frameworks for problem-solving.

The following diagram represents the Stacey Matrix, with the Y-axis indicating the clarity of requirements (from unclear to clear) and the X-axis representing the solution approach (from clear and proven to new and unproven). Projects are categorized into four types: simple, complicated, complex, and chaotic, based on the clarity of requirements and the approach to solutions.

Four Examples of Classification Into Individual Project Types

The structure of the Stacey Matrix becomes clearer when we illustrate the four areas of the individual project types using examples.

➑️ Simple Projects

A simple project is characterized by clearly defined requirements and a known approach. For example, using a familiar technology to fulfill well-established requirements qualifies as a "simple" or "trivial" project, where the solution is straightforward. In such cases, the traditional waterfall model is suitable for project management, as it involves working through predetermined steps without the need for extensive adaptation or iteration.

➑️ Complicated Projects

However, when either or both of these factors change, projects become more complex. For example, in IT, this might mean using a new technology that the team isn't fully proficient with, or implementing new requirements that haven't been addressed previously. In such cases, more time is needed for upfront planning and exploration, as the team is venturing into unfamiliar territory. Examples include adopting a new JavaScript library, entering a new market, or integrating a new invoicing system.

➑️ Chaotic Projects

It goes even further when both the solution approach (or technology) and the requirements are completely unknown - "chaotic". The question arises, how does one plan a project when neither the requirements nor the approaches to be used are partly unknown? The answer is simple: one can't. Chaos can't be planned.

This is also the reason why, especially in IT, agile frameworks like Scrum or Kanban are used in this case. When neither the requirements or the approaches are known, one must gradually approach the supposed goal.

The current most famous examples of Chaotic problems in consulting are the economic crisis, a pandemic like COVID-19, or wars.

➑️ Complex Projects

However, between the complicated and the chaotic area lies another area called "complex". In a complex system or project, the boundary conditions - requirements and approaches - can be set and left unchanged so that the system can self-organize within these boundaries.

A consulting example for this is the development of a new business model or the introduction of a new product.

The Problem Statement in the Case Interview

The Stacey Matrix is a tool for decision-making that helps identify problems in case interviews. It considers the chosen solution approach and the team's familiarity with methods to determine the implementation strategy and the type of case.

πŸ‘‰ Solve 200+ cases in our Case Library now!

By using the Stacey Matrix for the case at hand or the respective project, clarity is created for the upcoming tasks. By first determining the 'What' requirements on the Y-axis and then defining the 'How' on the X-axis, the solution path and implementation can be derived.

Advantages and Disadvantages of Using The Stacey Matrix in Consulting

The use of the Stacey Matrix in consulting primarily serves to visualize the problem at hand. This results in advantages and disadvantages of using it in a case interview, with the client or within projects:

Advantages:

  • The Stacey Matrix is quickly drawn by hand on a flip chart or paper to explain the situation to stakeholders.
  • All stakeholders can evaluate projects upfront, identifying potential frustrations early.
  • It uncovers challenges and responsibilities early, influencing personnel decisions.
  • The division into 'What' and 'How' clarifies argumentation and approach structuring.

Disadvantages:

  • In practice, 'What' is typically decided by higher management, not 'How', making complete classification challenging.
  • The Matrix doesn't suggest approaches to the problem. Participants with varying experience levels may assess projects differently.
  • It's a model and doesn't consider real-world factors like project environment, resources, and time constraints.
  • Depending on how it's used, the Stacey Matrix can be manipulated to fit one's agenda, potentially shaping the project to fit a predetermined approach rather than adjusting the approach to fit the project.

Conclusion on the Stacey Matrix

Especially in agile or digital transformation projects, the Stacey Matrix is a frequently used tool to determine the complexity of corporate structures, processes, and projects. Specifically in the area of decision-making in complex or chaotic situations, it can help to find a suitable project management approach as quickly as possible.

πŸ’‘ Depending on experience, however, one should be careful that the actual purpose of the Matrix is not subordinated to one's own interests, for example, to select a specific, familiar solution approach (Waterfall, Lean, Agile).

Practice Cases with the Stacey Matrix

Why not apply the Stacey Matrix in realistic case studies! We've compiled three fitting cases for you. Don’t forget: practice makes perfect! πŸ’ͺ

πŸ‘‰ PrepLounge case: Pharma R&D

πŸ‘‰ Expert case by Cristian: GreenLife Bank expands into Asia

πŸ‘‰ MBMC Case: Exploring the future of automotive mobility

How likely are you to recommend us to a friend or fellow student?
0 = Not likely
10 = Very likely
You are a true consultant! Thank you for consulting us on how to make PrepLounge even better!