Wizard of Oz Prototyping: What It Is, How & Why It's Done

  • #Prototyping
  • #UserResearch
wizard of oz prototyping

The Basics of Wizard Of Oz Prototyping

To understand the concept of Wizard of Oz (WoZ) prototyping, let’s first talk about what we mean by a prototype. Essentially, and for our purposes, a prototype is an early model or release of a website or app built to test a concept, process, or function. 

Just like the wizard pulling the strings behind the curtain in The Wizard of Oz, a design team can fake features so that the user thinks that the responses are computer-driven when they are actually human-controlled so they’re testing a simulation of the functionality. Once you know the important functions, you can then refine them through more in-depth user testing.  

WoZ prototyping is often used in rapid development — the quick creation of a full-scale model. The aim is to improve the user experience (UX) and can be helpful for user interface (UI) design and usability. You can learn more about UX, UI, and usability.

Testing new websites, redesigns, or apps can be a time-consuming process, and often costly. WoZ prototyping aims to reduce the amount of time and money by testing functionalities not yet implemented. You can determine which are necessary and which are not by faking the functionality you want to test with your users.

What Is The Wizard Of Oz Methodology?

The Wizard of Oz methodology is an easy way to test a user’s interaction with a website or app. It makes it possible to test a concept or design by having a moderator lead a face-to-face session with each user. 

You then have a designated “wizard” behind the scenes who controls the responses sent to the user. This makes it appear that the responses to the user are a result of the interaction with the technology itself.

When Is It Needed?

When it comes to any testing methodology, there are those suited to some situations but not for others. So it makes sense that the Wizard of Oz methodology isn’t ideal testing for all situations. 

What’s the best use then? 

It’s best used when there’s a need to simulate digital systems like websites or apps, and especially for artificial intelligence (AI) and augmented reality, as well as testing out new functionality. 

It can help designers and developers first learn if an idea is useful and wanted before investing a great deal of time and money in coding.

This type of testing can also help ensure that your design concept works as intended, so it’s ideal for UI design. And, it can help determine if users are able to use your product as it’s intended, which benefits your UX.

Testing Functionalities Before They Exist

Before you begin WoZ testing, you need to have a solid understanding of what functionality you wish to test. The functionality you’re testing will help determine the prototype design. It will also allow you to create the scripts necessary to conduct the testing. So, begin by defining what you want to learn or explore from the testing.

Determining The Simulation of Functionality

When you know what you’re testing and why you can begin to design your prototype and decide how you want it to simulate the functionality you’re testing. Will a wireframe work or maybe you need a simple digital version? How will you simulate the responses for the user? What’s the role of the wizard?

How It Works

The key to WoZ prototyping lies in building the prototype. The prototype should be easy to use and allow the wizard to quickly respond to the tester’s actions, ideally with a single click. 

In order to build the prototype, you need to know what functionality you want to test and then make the prototype fake the functionality. It should give the user a realistic experience with their interactions as if they were interacting with a website or app. 

To make the process run smoothly, you’ll also need to develop a script that gives directions for what’s to take place, a designated person to play the wizard role, and your tester who plays the role of the end-user.

Source: Pexels
Source: Pexels

What Tools Should You Use?

Part of figuring out how to simulate functionality involves identifying what tools and technologies you might use. You may not have to reinvent the wheel here, simply take advantage of existing tools such as email systems, instant messaging, Powerpoint presentations, or interactive wireframe tools like Adobe XD.

What Is Being Evaluated?

In order for WoZ methodology to give you answers, you need to set forth testing protocols so you can make sense of what you’re observing or the overall test results and what they mean. Define how you will observe, what type of data you want to collect, and how you plan to collect and record that data.

Who Should Be On Your Testing Team?

Typically, the team involved in testing can differ depending on your product, organization, and a host of other criteria. However, there are a few specialists that should always be involved in this process. Here they are: 

  • UX researchers—these specialists are simply irreplaceable during testing. These professionals’ skill sets revolve around empathizing with users, diving deep into their needs, and identifying the potential solutions for the problems users encounter. As a result of involving them in testing, UX researchers can help extract a wide array of actionable insights that will help your product improve and evolve. 
  • Developers—while these specialists are predominantly involved in the development phase, they can still bring a lot of value in testing. Having them involved in the process will allow you to identify better technical solutions to address user needs as well as bring a variety of ideas to the table. 
  • Designers—having designers involved in testing is absolutely critical since they’re the people who are responsible for crafting the experiences and interactions for the end-users. More importantly, they are the people responsible for incorporating the insights collected during testing in the prototypes.

Common Applications

WoZ methodology can be used for almost any interface to aid in UI design. It works well for testing out new websites and apps. This type of testing can help designers and developers better understand navigational needs, how the user expects the technology to behave, and pinpoint issues with new functionality. 

WoZ methodology is also ideal when testing out AI-driven experiences. This is because the range of responses can be almost impossible to replicate through traditional prototyping such as wireframes or mockups.

The Process Behind The Methodology

The process for WoZ methodology is dependent upon what you’re testing, the goal of your test, and the level of fidelity of your prototype, which will affect how involved the wizard will be during the testing process. 

  1. Determine which functionality needs testing.

    Before you begin WoZ testing, you need to have a solid understanding of what functionality you wish to test. The functionality you’re testing will help determine the prototype design. It will also allow you to create the scripts necessary to conduct the testing. So, begin by defining what you want to learn or explore from the testing.

  2. Consider how to simulate the functionality.

    When you know what you’re testing and why, you can begin to design your prototype and decide how you want it to simulate the functionality you’re testing. Will a wireframe work or maybe you need a simple digital version? How will you simulate the responses for the user? What’s the role of the wizard?

  3. Test combinations of tools with human intervention.

    Part of figuring out how to simulate functionality involves identifying what tools and technologies you might use. You may not have to reinvent the wheel here, simply take advantage of existing tools such as email systems, instant messaging, Powerpoint presentations, or interactive wireframe tools like Adobe XD.

  4. Define testing protocols.

    In order for WoZ methodology to give you answers, you need to set forth testing protocols so you can make sense of what you’re observing or the overall test results and what they mean. Define how you will observe, what type of data you want to collect, and how you plan to collect and record that data.

In order for WoZ methodology to give you answers, you need to set forth testing protocols so you can make sense of what you’re observing or the overall test results and what they mean. Define how you will observe, what type of data you want to collect, and how you plan to collect and record that data.

Varying Fidelity With Prototypes

Not all prototypes are created equally nor created as realistic as the final product. This is where the fidelity of the prototype comes into play. 

Source: Pexels
Source: Pexels

Fidelity refers to the degree to which your prototype reproduces the state and behavior of the real-world feature or condition. It’s basically the measure of the realism of the prototype. The fidelity can vary in the areas of the content, design, and interactivity and is broken down into three levels: low, medium, and high.

  • Low Fidelity

    Low-fidelity prototypes are often paper-based and range from hand-drawn to printed mockups that can easily translate the product and design concepts. They don’t allow for user interaction, but are still helpful in the early visualization or for any alternate design solutions and concepts that can lead to better UX.

    Low-fidelity prototypes are far less expensive and quicker to create. They can be beneficial during the early stages of development and testing because the users understand that it’s not a finished product and are more likely to be honest with suggestions and feedback.
  • Medium Fidelity

    Medium fidelity prototypes are also limited in their functionality, but include elements like clickable areas that indicate the interactions and navigation of a website or app. This level of fidelity is more suited to validating interaction concepts.

    Medium fidelity prototypes should more accurately depict the layout, provide more detail to specific components, like differentiating buttons from text-only links, while still avoiding the use of final images, fonts, and colors.
  • High Fidelity

    Where low-fidelity prototypes are paper-based, high-fidelity prototypes will appear and function as similar as possible to your finished product. They’re computer-based, allowing for realistic user interactions. When using high-fidelity prototypes for testing, you’re able to better collect human interaction or performance data. They’re also ideal in using to demonstrate the website or app to others, especially key stakeholders.

WoZ Prototyping Benefits UX, UI, And Usability

WoZ prototyping has many benefits, especially when it comes to improving UX, UI, and usability. It can benefit your UX design, which is crucial in retaining your end users. On top of that, WoZ prototyping can also save you time and money. 

You’re able to test functionalities without committing to extensive coding and development. This means you can test quicker and more frequently as you make enhancements and improvements to your product. 

When you’re able to better work out the kinks in the early stages of development, you’ll end up with a much higher quality product in the end, which your customers will appreciate.  

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Abdul Suleiman
Abdul SuleimanChief Experience Officer
Abdul Suleiman

Abdul has helped over 40 Fortune 500 companies make informed user-centered design decisions through evidence-based user research and UX best practices. As an Adjunct Professor, Abdul has taught in DePaul University’s graduate UX programs and for nine other universities.

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