In UX research, we have two pieces— hypotheses and success criteria — that set the foundation for any research activity. Without them, research risks becoming vague “user feedback sessions” rather than a fuel that powers design process.
A hypothesis is simply an assumption about user behavior, needs, or preferences that you want to validate (or invalidate). Think of them as “bets” you’re making in your design. I typically use the following format for a hypothesis:
I believe that [user group] will [do something/use something] because [reason or context].
Examples:
- I believe that first-time users will skip account setup if it feels too long, because they want immediate value.
- I believe that users will prefer voice search for recipes over typing because they often have their hands busy in the kitchen.
- I believe that users will need export-to-PDF functionality, because they are required to share reports in that format.
Once you articulate a hypothesis, the next thing you need to do is to validate it. And here comes a second piece of the UX research puzzle — success criteria. Success criteria are measurable signals that tell you whether your hypothesis holds true. They prevent you from interpreting vague feedback as validation.
Success criteria can be quantitative (numbers) or qualitative (observations), depending on the research context. Here is a 3-step process that I follow when choosing success criteria for my UX research:
1. Tie it to the research objectives
Before defining success, understand the specific problem the UX research aims to solve and how it connects to broader business objectives.
Start with two big questions:
“What do we need to learn to move this product forward?”
“Why do we need to learn it?”
and turn that into a measurable outcome.
Success criteria should answer the research questions. For example, if you’re checking if onboarding is intuitive, you can focus on quantitative success criteria, such as 80% of participants can complete onboarding without guidance.
2. Choose the right measurement type
There are three main categories of success criteria:
a. Behavioral (what users do)
This type explains what users do in your product, and it typically measures users’ activities and actions. Examples of success measurements are:
- Task success rate (% of participants completing a task).
- Error rate (% who took a wrong path or needed correction).
- Time on task (How long it takes to finish a certain task).
- Path taken (Did they follow the intended flow or work around it?).
b. Attitudinal (what users feel/think)
Attitude is how people think and feel about your product. Attitude is based on both the rational and emotional impact of user interaction.
- Satisfaction ratings (e.g., SUS, UMUX-Lite, or a 1–5 Likert scale).
- Confidence ratings (“How confident are you that you did this correctly?”).
- Preference signals (e.g., majority choosing one option over another).
c. Business-facing
While behavior and attitude are something that we can directly connect to attributes of product design, such as functionality, reliability, usability, and delight, business-facing measurement is about the business model of your product and how people think about it. To define success criteria for UX research, you need to align with business objectives.
- Willingness to pay (for validating pricing model).
- Net Promoter-like intent (e.g., “Would you use this again?”).
- Conversion intent (click-through, signup interest).
Most UX research benefits from a mix of different methods, not just one type. For example, if you’re validating a new search feature for your online store, you can choose
- Behavioral: 80% find the right product within 1 min.
- Attitudinal: Avg. satisfaction ≥4/5 on search experience.
- Business-facing: ≥60% say they’d use search as their primary navigation method.
Quick tip: If you want to have a balanced set of metrics, you can use frameworks like SMART (Specific, Measurable, Achievable, Relevant, Time-bound) or OKR (Objectives and Key Results).
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3. Consider the stage of product design process
Different stages of product design require a different set of success criteria. For example:
- Early phase of product design (prototypes) → Lean more on attitudinal (“Do they get it?” “Do they like it?”).
- MVP → Add behavioral (“Can they do it?” “How long does it take?”).
- Launched product → Add business-facing (“Does this drive signups, retention, revenue?”).
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How to Define Success Criteria for UX Research was originally published in UX Planet on Medium, where people are continuing the conversation by highlighting and responding to this story.