Oct 5, 2026 · 1 hr · 11 segments
Send us Fan Mail How many users do you actually need for a usability study? In this episode of The Design Psychologist, Thomas Watkins talks with…
Thomas WatkinsHost
Yeah, and, you know, kind of on these topics of test planning, real goals, finding out things that are beyond what you originally might have imagined, one of the things you write a lot about is, you know, aligning to the real goals of stakeholders and discovering what people actually want because they might say, hey, I want to make sure this website is good or make sure this product works, but there might be and are opportunities real goals that we really need to target.
Of who it is we're serving, right? And then we have our internal customer, which is those who are going to consume our designs or the research or whatever it is that we're doing as UX or design professionals.
So one of the biggest things that we're doing when we're doing user research is that we're providing decision support.
It's like, what kind of decisions need to be made? What is the risk of making, not making them? What is the risk of addressing something? What is the risk of missing something? So we want it to be reliable.
But no, we are not, and let me be very clear, I am not advocating that we go out and test 30 users every time.
I'm advocating that we assess the risk up front of, okay, what if we're wrong? And maybe we only need four or five.
I usually prefer somewhere, when I'm just doing straight up, seeking some data to solve the big things.
I do want to give some chance for finding things, so I may test anywhere from 7 to 12.
This is me telling you, you're the expert, and I want you to look at what's happening in the business.
So sometimes it is going to be about speed and getting speed to data and speed to decision-making.
And then I also look for where something is off that I know from my long expertise is going to be off for the end user and consumer.

Yeah, and, you know, kind of on these topics of test planning, real goals, finding out things that are beyond what you originally might have imagined, one of the things you write a lot about is, you know, aligning to the real goals of stakeholders and discovering what people actually want because they might say, hey, I want to make sure this website is good or make sure this product works, but there might be and are opportunities real goals that we really need to target.
Of who it is we're serving, right? And then we have our internal customer, which is those who are going to consume our designs or the research or whatever it is that we're doing as UX or design professionals.
So one of the biggest things that we're doing when we're doing user research is that we're providing decision support.
It's like, what kind of decisions need to be made? What is the risk of making, not making them? What is the risk of addressing something? What is the risk of missing something? So we want it to be reliable.
But no, we are not, and let me be very clear, I am not advocating that we go out and test 30 users every time.
I'm advocating that we assess the risk up front of, okay, what if we're wrong? And maybe we only need four or five.
I usually prefer somewhere, when I'm just doing straight up, seeking some data to solve the big things.
I do want to give some chance for finding things, so I may test anywhere from 7 to 12.
This is me telling you, you're the expert, and I want you to look at what's happening in the business.
So sometimes it is going to be about speed and getting speed to data and speed to decision-making.
And then I also look for where something is off that I know from my long expertise is going to be off for the end user and consumer.
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