Prototype Testing: Guide to Successful Development (2023 Update)

Published on June 2, 2023. Last update on: June 2, 2023.

You could argue that testing prototypes is just as important as building prototypes. And that's why we help you on your way in this guide. We explain what a prototype test is, which methods you can use, in which phase you carry out prototype tests, and how to get started with prototype testing.

1. What is a prototype?
2. What is a prototype test?
3. Examples prototype test
4. Why do you test a prototype and what are the benefits?
5. What methods do you use to test a prototype?
6. When should you test your prototype?
7. The iterative process of prototyping and testing
8. Preparing and executing prototype tests
9. Analyzing, interpreting and reporting prototype tests
10. Common prototyping challenges

Would you like to know more about testing prototypes? Download our free white paper on user testing. 

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What is a prototype?

A prototype is a visual representation of a concept or product idea in the form of a physical product,  digital interface, or sketches on paper. 

By visualizing a concept - also called prototyping - it becomes clear what the final product can look like. Prototyping allows companies to get feedback from potential end users through prototype testing. 

What is a prototype test?

In a prototype test, testers use a prototype and provide feedback so that deficiencies are identified and resolved before the product goes to market .

Prototype testing is an important part of UX research and these tests can be used at different points in the validation phase. With a prototype test, testers or respondents are always recruited from within the customer's target group.

Examples prototype test

Would you like to test a prototype yourself? Then use our free examples for prototype testing:

• Example questionnaire prototype test. Download a free example of a usability test questionnaire, and use it as inspiration when drawing up a test plan for your prototype research.
• Example research report. Download a sample research report to get an idea of ​​how to analyze and report the results of a prototype test.
• Example video prototype test. Check out one of our sample unmoderated user tests to get an idea of ​​what kind of feedback you can expect from users.

Why do you test a prototype and what are the benefits?

Now that you know what a prototype test is, it's time to understand why testing is so important. The advantages of testing prototypes are listed below:

1. Identifying problems and solutions. By testing your prototypes, you can identify potential problems before actually producing the product. You can see how users interact with your product and where there are opportunities for improvement. This allows you to address problems and explore possible solutions before investing valuable time and resources.
2. Collecting feedback from users. Testing prototypes allows you to collect valuable feedback from users. User experience is essential to the success of your product, and collecting feedback will help you understand how users experience your product, what they like, and what they struggle with. These insights can lead to important adjustments and improvements before you launch the product.
3. Optimization of functionality and user experience. Testing prototypes gives you the opportunity to optimize the functionality and user experience of your product. You can test different versions and iterations of your prototype to see which works best and appeals most to users. You can do this, for example, by performing user tests that include different variants.
4. Cost and time savings in the development phase. The biggest cost savings in prototyping is that changes can be implemented before the product is actually developed. Adjustments in a prototype are easier, faster and cheaper than adjustments in a product that is already fully developed.

What methods do you use to test a prototype?

There are various methods that can be used to test the extent to which a prototype fits the target group. The most common methods are listed in order:

1. Usability testing. Usability tests, or user tests, are performed to evaluate to what extent the prototype is usable and user-friendly. Users are asked to perform specific tasks with the prototype, while researchers collect observations and feedback. Characteristic of usability testing is that testers think aloud while performing a number of tasks. Usability testing helps identify usability issues, such as confusing navigation, unclear instructions, or problematic interaction designs.
2. A/B testing. A/B testing compares two different variants of the prototype to determine which one performs better based on predefined criteria. You can think of different versions of an interface, so that it can be investigated which version leads to a better user experience. These a/b tests are often performed in the form of user tests and can be both quantitative and qualitative in nature.
3. Focus Groups. For prototypes that have been implemented to a very limited extent, a focus group can be conducted to obtain feedback on the initial sketches and mock-ups and users can be asked to contribute ideas about the further development of the prototype.
4. Feedback sessions with stakeholders. In addition to user testing, feedback sessions can be held with stakeholders such as internal teams, customers, and experts. These sessions provide an opportunity to gather input and perspectives from various stakeholders. This can provide valuable insights and aid in decision-making regarding the prototype.
5. Functional tests. Functional testing focuses on assessing the functionality and performance of the prototype. The aim is to check that the prototype works correctly according to the specifications and requirements, but also to identify bugs. Functional tests can be performed by developers or testers to verify that the main functionalities of the prototype are working properly.

When should you test your prototype?

User Sense distinguishes three phases in the development process. The phase in the development process in which prototype tests are performed, is called the validation phase. In this phase, it is clear what needs the prototype must meet and studies are carried out to determine to what extent the solution - a concept or prototype - meets this need. Within the validation phase, prototype tests can be used at three different times:

1 - Conceptual phase: testing of mock-ups and non-interactive prototypes

This type of test is also known as an exploratory user test, where sketches or mock-ups of a website or app are tested and presented to the target group. You can use focus groups or user tests to test prototypes in the conceptual phase. Good to know: because the prototypes have been worked out to a very limited extent in the conceptual phase, the research question, objectives, and implementation can largely correspond to concept testing.

When testing prototypes in the conceptual phase, the focus is often on:

• Determine to what extent the prototype meets the needs of users.
• The general impression users have of the prototype.
• Finding out whether it is clear to testers what the pages are for.
• Discover what information testers expect to see at what time.
• Find out whether it is clear to testers what they should or can do with the prototype.

The biggest advantage of testing in the conceptual phase is that many insights are collected at an early stage, which can be used for the further development of the prototype. This means that as a company you do not have to steer much on assumptions and you know for sure that the prototype will be usable before major investments are made in further development.

2 - Interactive phase: testing of interactive prototypes

This kind of prototype test is also called the assessment test. In this phase, a prototype has been developed that looks 'finished' to the users. This means that there is a visual version of the prototype that testers can click through, which completely mimics the behavior of a real website or app. These prototypes are often created in Figma, Sketch, InDesign, Invision, Proto.io or Adobe XD.

To test these types of prototypes, it is best to conduct user testing, where you give testers the task of performing different tasks on the prototype and ask them to think aloud. These sessions can be conducted without an interviewer (unmoderated user tests) or with an interviewer (moderated user tests).

The focus when testing prototypes in the interactive phase is on:

• Actual performance of tasks with the prototype, and obtaining user feedback.
• Obtaining feedback on the navigation, such as the menu structure.
• Identify bottlenecks and ambiguities in the prototype.
• Determine what information is valuable and what information is missing.

Because this variant of prototype testing is performed before the first lines of code have been typed, the findings from the prototype research can be implemented quickly.

3 - Beta phase: testing a developed prototype

This type of test is also known as the validation or verification test. This test takes place at the end of the development cycle, just before the product is released to the market. Functional tests can be performed here, with developers performing as many different tests as possible to filter out any bugs. In addition to this, user tests can also be performed, where testers often perform a number of tasks on the website without an interviewer.

In this phase the focus of the prototype tests is on:

• Identifying bugs so that they can be fixed before going live.
• Determine whether testers are able to achieve the most important conversion tasks.
• Collecting quantitative data from usability metrics such as the SUS, NPS, SEQ, time-on-task, and task-completion rate.

The biggest benefit of testing at this stage is that it helps identify bugs and major obstacles for users, so that they can be resolved before the final product hits the market.

The iterative process of prototyping and testing

Characteristic of design thinking and developing prototypes is that the process is iterative. This means that you develop a prototype, perform prototype tests, process feedback and make adjustments until you and the end users are satisfied with the end result. In many cases this can already be achieved after a first round of testing, but more complex solutions may require several prototype tests. Conducting prototype tests online makes it possible to do this, without the costs spiraling out of control.

Preparing and executing prototype tests

Now that you understand why prototype testing is so important, let's take a look at the testing process itself. Here are the steps you need to follow for successfully testing prototypes:

1. Defining test goals and criteria. Start by setting clear test goals and criteria. What exactly do you want to achieve with the tests? What aspects of your prototype do you want to evaluate? By setting specific goals and criteria, you can run targeted tests and get valuable results.
2. Selection of test methods and techniques. As described above, there are several test methods and techniques you can use when testing prototypes. Choose the methods and techniques that best suit your specific product and goals.
3. Drawing up a test plan. A well-thought-out test plan is essential for a successful prototype test. The test plan should include the test objectives, methods, tasks, timelines, and stakeholders involved. This helps you to run the tests in a structured and organized manner and ensures that all relevant aspects are covered.
4. Run the tests and collect data. Now it's time to run the tests and collect data. Follow the test plan and perform the tests carefully and objectively. Capture all relevant data and feedback so you can conduct a thorough analysis later. You do this automatically by using our tool.

Analyzing, interpreting, and reporting test results

After the execution of the prototype tests, you can get started with the analysis, interpretation, and writing up a research report. Here, we have prepared a step-by-step plan:

1. Collecting and organizing test data. Gather all the test data collected during the tests and organize it in a structured way. This can make analyzing and comparing data easier. You can use our tool for this.
2. Analyzing user feedback. Go through the collected user feedback, review any session recordings, and identify key insights and patterns. Look at the comments and suggestions from users and try to understand the reasons behind certain feedback.
3. Identifying patterns and trends. Analyze the data and look for patterns and trends. Are there any common problems users are experiencing? Are there certain aspects of the prototype that perform particularly well? Identify key findings that you can use to improve your prototype.
4. Create a research report. Create a research report describing the main findings, so that they can be shared with other stakeholders.
5. Making decisions based on the test results. Use the analysis of the test results to make informed decisions. Determine which adjustments and improvements need to be made and which direction to take in the further development of your product.

Common prototyping challenges

Below are some of the challenges you may encounter when you want to get started with testing prototypes. We also indicate how you could overcome these challenges.

1. Schedule. There is a lot to consider when developing a new concept, product, or service. It is therefore not uncommon for a prototype to be delivered later than expected. Make sure there is enough wiggle room in the planning, so that testing the prototype is not skipped under the guise of 'no time'.
2. Recruiting respondents. Recruiting respondents often takes longer than expected. Therefore, make sure that you start the recruitment process early on, or let us help you recruit respondents. 
3. Limited resources. Testing prototypes can be time and resource intensive. Therefore, consider testing prototypes completely digitally. This allows you to save a lot of time and money, without compromising the effectiveness of the test.
4. Involving the right stakeholders. It is essential to involve the right stakeholders in prototype testing. Be sure to gather feedback from users, as well as internal stakeholders such as designers, developers, and product managers.
5. Dealing with resistance to change. Some stakeholders may resist changes resulting from test results. It is important to communicate openly, explain the benefits of testing and iteration, and involve stakeholders in the process.