5 tips for running an effective usability test

Knowing and understanding why and how your users use your product can be invaluable for getting to the nitty gritty of usability. Where they get stuck and where they fly through. Delving deep with probing questions into motivation or skimming over looking for issues can equally be informative.

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Usability testing can be done in several ways, each way has its benefits. Put super simply, usability testing literally is testing how useable your product is for your users. If your product isn't useable users will not stick around or very often complete their task, let alone come back for more.

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What is usability testing?

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Usability testing is a research method used to evaluate how easy something is to use by testing it with representative users.

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These tests typically involve observing a participant as they work through a series of tasks involving the product being tested. Having conducted several usability tests, you can analyze your observations to identify the most common issues.

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We go into the three main methods of usability testing:

1. Moderated and unmoderated
2. Remote or in person
3. Explorative, assessment or comparative

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1. Moderated or unmoderated usability testing

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Moderated usability testing

Moderated usability testing is done in-person or remotely by a researcher who introduces the test to participants, answers their queries, and asks follow-up questions. Often these tests are done in real time with participants and can involve other research stakeholders. Moderated testing usually produces more in-depth results thanks to the direct interaction between researchers and test participants. However, this can be expensive to organize and run.

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Top tip: Use moderated testing to investigate the reasoning behind user behavior.

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Unmoderated usability testing

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Unmoderated usability testing is done without direct supervision; likely participants are in their own homes and/or using their own devices to browse the website that is being tested. And often at their own pace.  The cost of unmoderated testing is lower, though participant answers can remain superficial and making follow-up questions can be difficult.

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Top tip: Use unmoderated testing to test a very specific question or observe and measure behavior patterns.

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2. Research or in-person usability testing

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Remote usability testing

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‍Remote usability testing is done over the internet or by phone. Allowing the participants to have the time and space to work in their own environment and at their own pace. This however doesn’t give the researcher much in the way of contextual data because you’re unable to ask questions around intention or probe deeper if the participant makes a particular decision. Remote testing doesn’t go as deep into a participant’s reasoning, but it allows you to test large numbers of people in different geographical areas using fewer resources.

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Top tip: Use remote testing when a large group of participants are needed and the questions asked can be direct and unambiguous.

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In-person usability testing

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‍In-person usability testing, as the name suggests, is done in the presence of a researcher. In-person testing does provide contextual data as researchers can observe and analyze body language and facial expressions. You’re also often able to converse with participants and find out more about why they do something. However, in-person testing can be expensive and time-consuming: you have to find a suitable space, block out a specific date, and recruit (and often pay) participants.

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Top tip: In-person testing gives researchers more time and insight into motivation for decisions.

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3. Explorative, Assessment or comparative testing

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These three usability testing methods generate different types of information:

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Explorative testing

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‍Explorative testing is open-ended. Participants are asked to brainstorm, give opinions, and express emotional impressions about ideas and concepts. The information is typically collected in the early stages of product development and helps researchers pinpoint gaps in the market, identify potential new features, and workshop new ideas.

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Assessment research

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‍Assessment research is used to test a user's satisfaction with a product and how well they are able to use it. It's used to evaluate general functionality.

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Comparative research

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‍Comparative research methods involve asking users to choose which of two solutions they prefer, and they may be used to compare a product with its competitors.

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Top tip: Depending on what research is being done, and how much qualitative or quantitative data is wanted.

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Which method is right for you?

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Whether the testing is done in-person, remote, moderated or unmoderated will depend on your purpose, what you want out of the testing, and to some extent your budget. 

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Depending on what you are testing, each of the usability testing methods we explored here can offer an answer. If you are at the development stage of a product it can be useful to conduct a usability test on the entire product. Checking the intuitive usability of your website, to ensure users can make the best decisions, quickly. Or adding, changing or upgrading a product can also be the moment to check on a specific question around usability. Planning and understanding your objectives are key to selecting the right usability testing option for your project.

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Let's take a look at a couple of examples of usability testing.

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1. Lab based, in-person moderated testing - mid-life website

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Imagine you have a website that sells sports equipment. Over time your site has become cluttered and disorganized, much like a bricks and mortar store may. You’ve noticed a drop in sales in certain areas. How do you find out what is going wrong or where users are getting lost? Having an in-person, lab (or other controlled environment), moderated usability test with users you can set tasks, watch (and record) what they do.

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The researcher can literally be standing or sitting next to the participant throughout, recording contextual information such as how they interacted with the mouse, laptop or even the seat. Watching for cues as to the comfort of the participant and asking questions about why they make decisions can provide richer insights. Maybe they wanted purple yoga pants, but couldn’t find the ‘yoga’ section which was listed under gym rather than a clothing section.

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Meaning you can look at how your stock is organised, or even investigate undertaking a card sort. This provides robust and fully rounded feedback on users behaviours, expectations and experiences. Providing data that can directly be turned into actionable directives when redeveloping the website. 

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2. Remote, moderated assessment testing - app product development

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You are looking at launching an app for parents to access for information and updates for the school. It’s still in development stage and at this point you want to know how easy the app is to use. Setting some very specific set tasks for participants to complete the app can be sent to them and they can be left to complete (or not). Providing feedback and comments around the usability.

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The next step may be to use first click testing to see how and where the interface is clicked and where participants may be spending time, or becoming lost. Whilst the feedback and data gathered from this testing can be light, it will be very direct to the questions asked. And will provide data to back up (or possibly not) what assumptions were made.

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3. Moderated, In-person, explorative testing - new product development

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You’re right at the start of the development process. The idea is new and fresh and the basics are being considered. What better way to get an understanding of what your users’ truly want than an explorative study.

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Open-ended questions with participants in a one-on-one environment (or possibly in groups) can provide rich data and insights for the development team. Imagine you have an exciting new promotional app that you are developing for a client. There are similar apps on the market but none as exciting as what your team has dreamt up. By putting it (and possibly the competitors) to participants they can give direct feedback on what they like, love and loathe.

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They can also help brainstorm ideas or better ways to make the app work, or improve the interface. All of this done, before there is money sunk in development.

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Usability testing summary: When to use each method (and why)

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Key objectives will dictate which usability testing method will deliver the answers to your questions.

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Whether it’s in-person, remote, moderated or comparative with a bit of planning you can gather data around your users very real experience of your product. Identify issues, successes and failures. Addressing your user experience with real data, and knowledge can but lead to a more intuitive product.

When it comes to financial services, user experience goes way beyond just making things easy to use. It’s about creating a seamless journey and establishing trust at every touchpoint. Think about it: as we rely more and more on digital banking and financial apps in our everyday lives, we need to feel absolutely confident that our personal information is safe and that the companies managing our money actually know what they're doing. Without that trust foundation, even the most competitive brands will struggle with customer adoption.

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Why Trust Matters More Than Ever

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The stakes are uniquely high in financial UX. Unlike other digital products where a poor experience might result in minor frustration, financial applications handle our life savings, investment portfolios, and sensitive personal data. A single misstep in design can trigger alarm bells for users, potentially leading to lost customers.

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Using UX Research to Measure and Build Trust

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Building high trust experiences requires deep insights into user perceptions, behaviors, and pain points. The best UX platforms can help financial companies spot trust issues and test whether their solutions actually work.

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Identify Trust Issues with Tree Testing

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Tree testing helps financial institutions understand how easily users can find critical information and features:

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• Test information architecture to ensure security features and privacy information are easily discoverable
• Identify confusing terminology that may undermine user confidence
• Compare findability metrics for trust-related content across different user segments

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Optimize for Trustworthy First Impressions with First-Click Testing

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First-click testing helps identify where users naturally look for visual symbols and cues that are associated with security:

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• Test where users instinctively look for security indicators like references to security certifications
• Compare the effectiveness of different visual trust symbols (locks, shields, badges)
• Identify the optimal placement for security messaging across key screens

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Map User Journeys with Card Sorting

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Card sorting helps brands understand how users organize concepts. Reducing confusion, helps your financial brand appear more trustworthy, quickly:

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• Use open card sorts to understand how users naturally categorize security and privacy features
• Identify terminology that resonates with users' perceptions around security

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Qualitative Insights Through Targeted Questions

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Gathering qualitative data through strategically placed questions allows financial institutions to collect rich, timely insights about how much their customers trust their brand:

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• Ask open ended questions about trust concerns at key moments in the testing process
• Gather specific feedback on security terminology understanding and recognition
• Capture emotional responses to different trust indicators

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What Makes a Financial Brand Look Trustworthy?

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Visual Consistency and Professional Polish

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When someone opens your financial app or website, they're making snap judgments about whether they can trust you with their money. It happens in milliseconds, and a lot of that decision comes down to how polished and consistent everything looks.Clean, consistent design sends that signal of stability and attention to detail that people expect when money's involved.

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To achieve this, develop and rigorously apply a solid design system across all digital touchpoints including fonts, colors, button styles, and spacing, it all needs to be consistent across every page and interaction. Even small inconsistencies can make people subconsciously lose confidence.

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Making Security Visible

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Unlike walking into a bank where you can see the vault and security cameras, digital security happens behind the scenes. Users can't see all the protection you've built in unless you make a point of showing them.

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Highlighting your security measures in ways that feel reassuring rather than overwhelming gives people that same sense of "my money is safe here" that they'd get from seeing a bank's physical security.

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From a design perspective, apply this thinking to elements like:

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• Real time login notifications
• Transaction verification steps
• Clear encryption indicators
• Transparent data usage explanations
• Session timeout warnings

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You can test the success of these design elements through preference testing, where you can compare different approaches to security visualization to determine which elements most effectively communicate trust without creating anxiety.

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Making Complex Language Simple

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Financial terminology is naturally complex, but your interface content doesn't have to be. Clear, straightforward language builds trust so it’s important to develop a content strategy that:

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• Explains unavoidable complex terms contextually
• Replaces jargon with plain language
• Provides proactive guidance before errors occur
• Uses positive, confident messaging around security features

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You can test your language and navigation elements by using tree testing to evaluate user understanding of different terminology, measuring success rates for finding information using different labeling options.

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Create an Ongoing Trust Measurement Program

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A user research platform enables financial institutions to implement ongoing trust measurement across the product lifecycle:

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Establish Trust Benchmarks

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Use UX research tools to establish baseline metrics for measuring user trust:

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• Findability scores for security features
• User reported confidence ratings
• Success rates for security related tasks
• Terminology comprehension levels

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Validate Design Updates

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Before implementing changes to critical elements, use quick tests to validate designs:

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• Compare current vs. proposed designs with prototype testing
• Measure findability improvements with tree testing
• Evaluate usability through first-click testing

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Monitor Trust Metrics Over Time

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Create a dashboard of trust metrics that can be tracked regularly:

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• Task success rates for security related activities
• Time-to-completion for verification processes
• Confidence ratings at key security touchpoints

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Cross-Functional Collaboration to Improve Trust

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While UX designers can significantly impact brand credibility, remember that trust is earned across the entire customer experience:

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• Product teams ensure feature promises align with actual capabilities
• Security teams translate complex security measures into user-friendly experiences
• Marketing ensures brand promises align with the actual user experience
• ‍Customer service supports customers when trust issues arise

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Trust as a Competitive Advantage

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In an industry where products and services can often seem interchangeable to consumers, trust becomes a powerful differentiator. By placing trust at the center of your design philosophy and using comprehensive user research to measure and improve trust metrics, you're not just improving user experience, you're creating a foundation for lasting customer relationships in an industry where loyalty is increasingly rare.

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The most successful financial institutions of the future won't necessarily be those with the most features or the slickest interfaces, but those that have earned and maintained user trust through thoughtful UX design built on a foundation of deep user research and continuous improvement.

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For those new to the qualitative research space, there’s one question that’s usually pretty tough to figure out, and that’s the question of how many participants to include in a study. Regardless of whether it’s research as part of the discovery phase for a new product, or perhaps an in-depth canvas of the users of an existing service, researchers can often find it difficult to agree on the numbers. So is there an easy answer? Let’s find out.

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Here, we’ll look into the right number of participants for qualitative research studies. If you want to know about participants for quantitative research, read Nielsen Norman Group’s article.

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Getting the numbers right

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So you need to run a series of user interviews or usability tests and aren’t sure exactly how many people you should reach out to. It can be a tricky situation – especially for those without much experience. Do you test a small selection of 1 or 2 people to make the recruitment process easier? Or, do you go big and test with a series of 10 people over the course of a month? The answer lies somewhere in between.

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It’s often a good idea (for qualitative research methods like interviews and usability tests) to start with 5 participants and then scale up by a further 5 based on how complicated the subject matter is. You may also find it helpful to add additional participants if you’re new to user research or you’re working in a new area.

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What you’re actually looking for here is what’s known as saturation.

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Understanding saturation

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Whether it’s qualitative research as part of a master’s thesis or as research for a new online dating app, saturation is the best metric you can use to identify when you’ve hit the right number of participants.

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In a nutshell, saturation is when you’ve reached the point where adding further participants doesn’t give you any further insights. It’s true that you may still pick up on the occasional interesting detail, but all of your big revelations and learnings have come and gone. A good measure is to sit down after each session with a participant and analyze the number of new insights you’ve noted down.

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Interestingly, in a paper titled How Many Interviews Are Enough?, authors Greg Guest, Arwen Bunce and Laura Johnson noted that saturation usually occurs with around 12 participants in homogeneous groups (meaning people in the same role at an organization, for example). However, carrying out ethnographic research on a larger domain with a diverse set of participants will almost certainly require a larger sample.

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Ensuring you’ve hit the right number of participants

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How do you know when you’ve reached saturation point? You have to keep conducting interviews or usability tests until you’re no longer uncovering new insights or concepts.

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While this may seem to run counter to the idea of just gathering as much data from as many people as possible, there’s a strong case for focusing on a smaller group of participants. In The logic of small samples in interview-based, authors Mira Crouch and Heather McKenzie note that using fewer than 20 participants during a qualitative research study will result in better data. Why? With a smaller group, it’s easier for you (the researcher) to build strong close relationships with your participants, which in turn leads to more natural conversations and better data.

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There's also a school of thought that you should interview 5 or so people per persona. For example, if you're working in a company that has well-defined personas, you might want to use those as a basis for your study, and then you would interview 5 people based on each persona. This maybe worth considering or particularly important when you have a product that has very distinct user groups (e.g. students and staff, teachers and parents etc).

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How your domain affects sample size

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The scope of the topic you’re researching will change the amount of information you’ll need to gather before you’ve hit the saturation point. Your topic is also commonly referred to as the domain.

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If you’re working in quite a confined domain, for example, a single screen of a mobile app or a very specific scenario, you’ll likely find interviews with 5 participants to be perfectly fine. Moving into more complicated domains, like the entire checkout process for an online shopping app, will push up your sample size.

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As Mitchel Seaman notes: “Exploring a big issue like young peoples’ opinions about healthcare coverage, a broad emotional issue like postmarital sexuality, or a poorly-understood domain for your team like mobile device use in another country can drastically increase the number of interviews you’ll want to conduct.”

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In-person or remote

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Does the location of your participants change the number you need for qualitative user research? Well, not really – but there are other factors to consider.

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• Budget: If you choose to conduct remote interviews/usability tests, you’ll likely find you’ve got lower costs as you won’t need to travel to your participants or have them travel to you. This also affects…
• Participant access: Remote qualitative research can be a lifesaver when it comes to participant access. No longer are you confined to the people you have physical access to, instead you can reach out to anyone you’d like.
• Quality: On the other hand, remote research does have its downsides. For one, you’ll likely find you’re not able to build the same kinds of relationships over the internet or phone as those in person, which in turn means you never quite get the same level of insights.

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Is there value in outsourcing recruitment?

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Recruitment is understandably an intensive logistical exercise with many moving parts. If you’ve ever had to recruit people for a study before, you’ll understand the need for long lead times (to ensure you have enough participants for the project) and the countless long email chains as you discuss suitable times.

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Outsourcing your participant recruitment is just one way to lighten the logistical load during your research. Instead of having to go out and look for participants, you have them essentially delivered to you in the right number and with the right attributes.

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We’ve got one such service at Optimal, which means it’s the perfect accompaniment if you’re also using our platform of UX tools. Read more about that here.

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Wrap-up

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So that’s really most of what there is to know about participant recruitment in a qualitative research context. As we said at the start, while it can appear quite tricky to figure out exactly how many people you need to recruit, it’s actually not all that difficult in reality.

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Overall, the number of participants you need for your qualitative research can depend on your project among other factors. It’s important to keep saturation in mind, as well as the locale of participants. You also need to get the most you can out of what’s available to you. Remember: Some research is better than none!