Exploring the top design thinking models that influence our industry

What is Human Centered Design?

Have you ever come across a door that you couldn’t figure out how to open? Sometimes, you’ll push a door, and realize it won’t move. Is it locked? Are you not allowed to use this door? Is it broken, somehow? Usually, no — you missed that it’s a door you have to pull to open, instead of push. But for whatever reason, you didn’t understand that, and as a result, you may feel silly or foolish for not noticing.

Realistically, it’s not your fault. It all depends on how the door was designed.

It’s most likely that the door was missing a clue, or a “signifier” that let you know how it works. Doors sometimes have handles on them that indicate how they operate. It’s common for a door with a big metal rod along the side of it to operate as a “pull”. That rod is a signifier telling you to pull it to open the door. Other doors have nameplates which tell you to “push” or to “pull”.

But sometimes, doors don’t feel “intuitive” to use. You’ll see something on the door that makes you think it’s a push, but in fact, it will only pull to open.

The issue of doors being non-intuitive is very common. So common, in fact, that someone made a video explaining the issue:

The issues with doors arise from their design — when making ANY experience for someone else, including something as simple as how a door opens, we have to think about who will use that experience. This consideration we apply to our designs is called Human Centered Design.

Human Centered Design is an approach to solve complex problems for others. It is the process in which we can consider those we design for. It is a unique form of design in that its purpose is rooted in solving the problems of other people.

The need for Human Centered Design occurs in our daily lives. It can be something complicated, like how doctors can operate sophisticated surgical equipment, or how an electrician can fix a power issue. Or, it could be something quite simple, such as turning on a faucet or using a stove.

The concept of Human Centered Design has many definitions, and takes many forms:

“Human Centered Design is an approach to creating a program, policy, service, or product that is tailored to the needs of the person who will use it or be impacted by it.”

–Bloomberg Cities

“It is based on a philosophy that empowers an individual or team to design products, services, systems, and experiences that address the core needs of those who experience a problem.”

–DC Design

“Human-centered design is an approach to problem-solving commonly used in design, management, and engineering frameworks that develops solutions to problems by involving the human perspective in all steps of the problem-solving process.”

–Wikipedia

All these definitions have the same structure:

• Human Centered Design is a process.
• It solves problems.
• It is based on the needs of others.

So when you design following the principles of Human Centered Design, you are designing using a process that enables you to solve the problems of other people.

The definition of Human Centered Design helps us understand what we should be doing. But how do we actually follow a process? How do we understand the needs of others? And how do we solve their problems?

Luckily, we can rely on design thinking to help. Design thinking is a process in which we can design. There are several design thinking models we can consider when it comes to our design practice.

Design Thinking Models

Aarron Walter’s Hierarchy of User Needs

Aarron Walter is an award-winning writer known best for his book Designing For Emotion. In it, he defines a framework called the Hierarchy of User Needs.

Aarron Walter takes Maslow’s Hierarchy of Human Needs and adapts it to design. Essentially, when interacting with an experience, that experience needs to have the following elements, in order of importance:

1. Functional
2. Reliable
3. Usable
4. Pleasurable

Think of these as a pyramid. Each aspect builds on itself, satisfying the user more and more deeply. Start by imagining an experience with none of these things. Perhaps something is beautiful, for example. If it’s not functional, it won’t satisfy the basic needs of the user, and its aesthetic will become unappreciated. Perhaps you’ve experienced this yourself, when interacting with a design that looks really good, but doesn’t make sense, or can’t be used.

The lowest level of a user’s needs is for an experience to be Functional. It needs to perform the basic task it promises to do by existing. If it doesn’t function, it will not meet the core needs of its users. By definition, it will be nonfunctional, or unusable.

Next, a product needs to be Reliable. If it is functional, but only some of the time, then it can technically be used, but won’t be able to be used on a consistent basis. Think of, for example, an unreliable internet connection. It functions, sure, but you can’t count on it to function all of the time, and as a result, you won’t be able to use it as well as a functional and reliable connection.

After being functional and reliable, it must be Usable. Usable may sound like Functional, but there are core differences that make this category higher on the Hierarchy of User Needs. Usable means that a product is easy to learn, discover, and utilize. A user shouldn’t have to search for functionality, rather, it should not require much effort to operate. A usable product is one that not only works, but works well.

Lastly, a product must be Pleasurable. It is not enough for products to work well to reach this level of satisfaction in the Hierarchy of User Needs. They have to be delightful to use, and produce joy when used. Perhaps they solve a user’s problem really well, or they are aesthetically enjoyable to use. They have such a deeply satisfying user experience that users are not only able to use the product well, they have a good time doing so.

Don Norman’s Design of Everyday Things

Don Norman is famous in the design industry. Many consider him to be the “grandfather” of the term UX, or, User Experience. He wrote a book called The Design of Everyday Things which goes into great detail about our door problem. In it, he proposes a four step process for creating a good user experience:

1. Observe
2. Ideate
3. Prototype
4. Test

First, we must Observe. We have to understand the people we want to design for. We need to see how they act, what their problems are, and how they move around their environment. Through this process of observation, we take notes and record our findings, to allow us to form an opinion on what the problems to solve are, so that we can move on to the next step in the process — ideation.

Next, we Ideate. From our observations, we think of ways we can solve our users’ problems. We brainstorm, sketch, and create various ideas that could work. We spend time thinking of wild and crazy ideas, and eventually pair down to a couple that we think will work best.

After we ideate, we Prototype. From our best ideas, we start to develop a functional representation of those ideas to show our users. We create digital mockups, or even use pieces of paper to represent our ideas in a fast, iterative way with the purpose of getting feedback early, often, and quickly.

After we prototype, we Test. Testing is a valuable way to gain feedback from others to see how they actually use our ideas. We use the prototypes we made and share them with actual people to see how they would use our designs. We test to see how intuitive our product is, how desirable it would be, and, above all, to see if our ideas actually would solve the problem users experience.

Don Norman’s original design thinking process is the core of modern design thinking. We observe, we ideate, we prototype, then we test. This model has had several revisions and interpretations to it, in order to create various design thinking frameworks that help improve the Human Centered Design practice.

IDEO’s Human Centered Design Process

IDEO, a world renowned design agency, offers a variation on Don Norman’s design thinking model. They think of Human Centered Design as three steps:

1. Inspiration
2. Ideation
3. Implementation

Similar to Don Norman’s method, this method involves observation, ideation, prototyping, and testing. However, it builds on his model by showing how we can diverge and converge during that process.

We start with Inspiration. We know we have some problem to solve for our users, but we might not know the details. How can we become inspired? Here, we diverge — we look at various resources and obtain different sources of information in order to gain the most inspiration. This of yourself as an explorer — you are seeking out the most information possible in order to know as much as you can about the problem space.

Then, we move on to Ideation. We have recognized we have an opportunity to design. How do we make sense of it all? How do we interpret what we have learned and turn it into an idea? This is where we converge — we need to take all of our information from the Inspiration step and make it make sense. We need to form opinions, and create hypotheses, as we prepare to think of the ideas we believe will solve our users’ problems. During this step, we diverge again — once we form those opinions and make sense of our observations, we diverge to think of solutions. We brainstorm, and we sketch, and we create various ideations that eventually become prototypes for testing.

Lastly, we move on to Implementation. Now that we have a solution, we need to see if that solution works. We find users, test with them, and observe how our solution functions in the hands of others. We converge again — as we test, we narrow down our ideas and see what works and what doesn’t. From our testing, we begin to build our solution, implementing our ideas into functional products.

The Double Diamond

The process of diverging and converging repeatedly is common in design thinking models. Like IDEO’s model, the British Design Council has created a method that relies on diverging and converging as we conduct the design process called the Double Diamond.

The Double Diamond is a great way to think about the design process as it relates to a specific problem in search of a singular solution. It lends itself well to design engagements that have a single, clear cut set of deliverables and timeline. It is broken up into four steps:

1. Discover
2. Define
3. Develop
4. Deliver

The Double Diamond Process begins with a Problem. It is the start of the design thinking process that will flow through the entire project. Everything in this model hinges on the problem, and each design step incorporates this.

First, we Discover. After we learn of the Problem, we must learn more about it. What is that problem? How does it relate to users? How do users move around this problem? Are there others that have solved this problem before? What do they do, and how do they do it? This step is all about research — researching users, competitors, and technological solutions that have this problem. In this step, we are explorers, diverging from the problem and researching all the things we can think of related to it.

Next, we Define. This is where we start to converge — after learning everything we can about the Problem, we try to define what the real problem is, or the “Problem to Solve”. This problem definition is crucial to the success of the project — it is what we will ideate against, and what we will try to deliver a solution for. All of our research during this step converges to a singular point — the Problem Definition, which is our Problem to Solve.

The Problem to Solve is the turning point in the project. Once we understand this, we are prepared to diverge again, except this time, with a better understanding of what we are trying to accomplish. This is where we create a Design Brief, which explains clearly everything we learned in the Discover and Define steps of the project. It is this Problem to Solve that we want to ideate around and deliver a solution for.

Next, we Develop. Here, we diverge again — now that we understand the problem, we must come up with solutions to it. We ideate, brainstorming solutions and sketching ideas until we hit a critical mass of different options. Then, we begin to evaluate those options and prepare prototypes that allow us to test them.

Finally, we Deliver. We take our ideas from the Develop step and test them. We show users our ideas, gain their feedback, and make revisions as we converge towards our solution to the Problem to Solve.

NNGroup’s Design Thinking Process

The Nielsen Norman Group (“NN/G”) offers a comprehensive model for the design thinking process. It’s broken up into six steps of design, across three phases.

1. Empathize
2. Define
3. Ideate
4. Prototype
5. Test
6. Implement

Under the NN/G’s design thinking model, we must first Empathize. We have to understand our users, the problem, and the context. We must imagine what it is like to encounter this problem, and learn how people interact with it.

Then, we must Define. After we learn of the problems our users face, we must define those problems and determine the Problem to Solve. What will we try to solve, on behalf of our users?

Afterwards, we must Ideate. Once we have a clear understanding of the Problem to Solve, we must think of solutions that could work for them. We must brainstorm, and sketch, and create ideas that could solve their problems.

After we ideate, we must Prototype. This is where we create representations of our ideas, with the intent to test them. Our representations should allow others to see our ideas and interact with them, so that we may learn more about how they would be received.

Next, we Test. Once we have our prototypes, we find users and share our ideas with them. We test our ideas, not our users, and see how well our ideas hold up. We challenge our hypotheses and see if our ideas are usable and can solve users’ problems.

Finally, we Implement. Once we know how our ideas work, we build our ideas and deliver them to users. We turn our prototypes into functional products, and release those products to the world for our users to use.

The Design Thinking Process

Each of the design thinking models we have discussed are appropriate ways to practice Human Centered Design. In your practice, you may prefer one model to another, and that’s totally acceptable. Design practitioners around the world use different models, some not covered here as well.

For our purposes, let’s zoom in on NNGroup’s process. This is because of several reasons:

1. The NNGroup’s model is iterative.

The NNGroup’s design thinking model allows for iteration during each step of the process. In practice, design is rarely a linear process. Commonly, you will learn things in each step of the process that will incentivize you to return to an earlier stage of the process. You may learn during testing that you didn’t think of a possible use case, and as a result, will want to return to Ideation to think of new ideas. Or, you will implement your solution, and see that you solved part of the problem, but not all of it, so you want to return to Empathize and start again. This model leaves us the room to do so.

2. The NNGroup’s model is detailed.

Because their design thinking model is broken up into six steps, each step ends up getting a lot of detail and clarity. For example, the Implement step explicitly focuses on delivering a solution, such as, working with developers to create your idea. This level of specificity will allow us to deeply explore the full extent of the design thinking process.

3. It has phases that oversee its steps.

In addition to having six comprehensive steps, it also has three phases that oversee those steps: Understand, Explore, and Materialize. Each of these phases help us understand how the steps play into the overall design thinking process. First, we must Understand our users and the Problem to Solve, and we do so by empathizing and defining. Then, we must Explore what we can do for our users by Ideating and Prototyping. Then, we have to Materialize our solution by Testing and Implementing. In this way, we have a clear process with actionable steps that offer a concrete approach to Human Centered Design.

Let’s explore each of those steps in greater detail.

Empathize

In the first step of the design thinking process, it is our goal to get a better understanding of the problem we want to solve. We have several ways to do this.

Observe Others

To better empathize, we can start by observing others experience the problem. We can watch people complete tasks, or go through their lives, so that we can see how they encounter the problem and how they currently try to solve it. We can leverage user diaries, or contextual inquiries, or other methods that allow us to be observers and see the problem in action.

Experience the Problem

Alternatively, we can experience the problem ourselves. We can directly gain experience with the pain points of what we are trying to solve by completing tasks related to the problem. If it’s a product, we can try using it to see the problems with it. If it’s a process, we can go through that process to see how we experience it and how we feel during it.

Talk to Experts

Another technique we can use is to find experts related to the problem and speak with them about it. Experts could be industry leaders who have studied the problem, or who have solved similar problems. Or, experts could be users, people who encounter the problem frequently and have a lot of experience with it. We can interview these experts and learn more about the problem and how they deal with it.

Search for Solutions

Finally, we can search for solutions that already exist. If it’s a common or well known problem, it’s possible others have already solved it (or tried to solve it). Perhaps a solution exists that we can interact with, and take inspiration from, so that we can better solve the problem ourselves.

Define

In the second step of the design thinking process, we must begin to form opinions. We have to take the research from the first step of the process, synthesize it, then analyze the results. Here, we must accomplish several things.

What commonalities exist?

In our observations, we must categorize and sort our research. What trends or common points are present? Does everyone suffer in the same way? Does everyone have the same solution to the problem? Are there common issues that most people experience? We must draw parallels and from those parallels, be better informed to think of ideas later in the process.

How are people served?

From our observations, did we notice any solutions? Did we notice a lack of solutions in a certain aspect of the problem? Are people underserved in any capacity? By identifying where people are satisfied and dissatisfied, we can better focus on a solution.

What is the Problem to Solve?

In this step, we attempt to clearly define the Problem to Solve. We take our research and observations and form opinions on how people are struggling. We don’t think of a solution just yet; rather, we really try to well define what problems people have and what problem we specifically want to focus on for the remainder of the design thinking process. We may observe multiple problems, and that’s OK — it is in this step that we want to focus our attention so we can think of solutions that are specific to what we want to solve.

Ideate

In the third step of the design thinking process, we want to create solutions to our users’ problems. Here, we take our research and our Problem to Solve and both diverge, then converge around possible solutions.

Diverge around possibilities

First, we diverge. We go wide, thinking of all sorts of possible solutions that could solve the core problem users face. We brainstorm without restriction — no idea is “too crazy” during this step. We want to think of as many ideas as possible, then from those ideas, converge.

Converge around probabilities

After truly exploring possible ideas through brainstorming, sketching, and other ideation techniques, we converge. We compare ideas against each other, evaluating through the lenses of the ones we think could best solve our users’ problems, or the ones that are most feasible. We prioritize ideas, so that we can test them with users.

Prototype

In the fourth step of the design thinking process, we want to create representations of our ideas, to see how they perform. We need to take our ideas and give them shape, so that we can see how they function in the hands of other people.

Lean & Imperfect

In this step, it’s not about perfection, it’s about gaining information. We need to validate our ideas, not create a fully functional product. It’s a waste of time to create a perfect, fully coded or functional idea to test. We want something quick, yet accurate enough to give people an idea of how our solution could work. Create the smallest, minimum viable idea that will let you test your solution.

Tactile

Our ideas need to be tested with others. Whatever you prototype, it has to be able to be used by others. This could be something as complex as a high fidelity mockup of every screen in your product, or as simple as a few pieces of paper you could show someone to give them a rough sense of your idea. So long as it conveys your idea, it can work.

Test

In the fifth step of the design thinking process, we must test our ideas. After creating representations of those ideas, we must see how users interact with them, so that we can test our assumptions and learn if our solution actually solves users’ problems.

Is it usable?

When people interact with your prototype, is the solution usable? Do people know how to navigate it? Have you clearly communicated the design in a way that satisfies their hierarchy of needs? Is it functional, reliable, usable, and delightful? It’s OK if it isn’t as a prototype, so long as your testing suggests that it will be as a product.

Does it actually solve the problem?

Most importantly, does your idea satisfy the Problem to Solve? Have you created something that actually could solve your users’ problems? This is the time to learn whether or not that’s true, and if it’s not, how you can adjust the design so that it’s more likely their problems will be solved.

Implement

In the last step of the design thinking process, you must implement your solution. In this step, you are certain your ideas work — now, you must get them into the hands of your users.

What needs to be built?

How will someone create your solution? Will it need to be coded? Will you need a back-end architecture to keep it running? As you design your solution, you have to think of all the supporting structures that will be needed for your solution to exist in the real world.

How will users use it?

How will users interact with your solution? As a functioning product, you will need to think of all the use cases of your design. What if there is an error? What if a user starts using your product, then comes back to it at a later point? You have to consider more than just the “happy path” of your designs — you must deliver a fully thought out product experience that covers all edge cases a user could run into.

Choose the model that’s right for you

Realistically, any of these models can work — they are each designed to help teams arrive at the best conclusions they can for their product. Choose the model that works best for how your team works, or how you aspire for your team to work. Each one is centered around the goals you should strive for as a creator — the best possible outcome for your users.

Thanks for reading! I like to write about games, design, and UX. Read more here. Wanna chat? Connect with me on LinkedIn. Looking to work together? Check out my previous work.