14 Essential Product Design Interview Questions *
Toptal sourced essential questions that the best product designers can answer. Driven from our community, we encourage experts to submit questions and offer feedback.Hire a Top Product Designer Now
What analytics tools and key performance indicators (KPIs) do you use to evaluate product designs?
Great product designers seek to create experiences that work for specific audiences and use analytics and research data to compile a set of actionable insights and hypotheses. Garnering quantitative data on how people use a website or an application plays an essential role in a product designer’s arsenal of product success evaluation tools. Whereas user research typically focuses on qualitative data, analytics focuses on quantitative data.
Listen for extensive knowledge in quantitative product evaluation methods that capture large data sets from users to determine what issues there may be with the product, as well as what types of industry-standard analytics tools they use for product testing.
Successful product analysis will result in an actionable list of tweaks and enhancements that once implemented, will show measurable improvement to the product’s user experience. Product designers assess which will have the most impact on conversion rates and create wireframes and designs that feed into development. These may be conversion rate improvements and higher user engagement and retention.
There are many analytics tools and methods available that capture user behavior, e.g., eye-tracking, click-tracking heatmaps, and time-to-task-completion indicators. There’s “UI tagging,” which tracks specific elements in a product showing an analysis of how people interact with a product.
It’s best not to focus on the tool (Mixpanel, Pendo, Google Analytics, Optimizely, Adobe Target, etc.). Listen for the why, the methods they used, and what measurements they took. How did they choose a success metric? What key performance indicators (KPIs) were they evaluating? Did they employ some form of “objectives and key results” (OKR) methodology? For example, how many people converted to paying customers, moved through the onboarding process, clicked on a signup button, or set up 1-click ordering?
Product design is not the same as UX design; it encompasses UX design. Product designers do what UX designers do and more. UX designers focus on investigating behavioral patterns, explore the multitude of ways in which an application might solve a user need, and then set out to optimize a digital product’s user experience.
Product design is the whole process. It is about designing an experience holistically, where “the whole is considered more than the sum of its parts,” and maintaining this bias throughout the consumer lifecycle, along with all the touchpoints where a user will be interacting with a product.
Product designers are the caretakers of the foundation upon which the business depends. Discrepancies between what a brand promises and what the product delivers are, ultimately, what will cause a business to fail. It’s critical that a product designer works closely with the marketing team and understands what they do and why they do it.
When trying to solve design problems, UX designers are primarily concerned with the functionalities and aesthetics of a product that make up “the experience.” Product design goes beyond that; it considers human moments in context and incorporates all aspects of a product’s ecosystem.
A product designer helps identify, investigate, and validate a problem, then researches, designs, tests, and ships the solution.
A great product designer should be able to demonstrate knowledge describing the differences, in particular how UX design is only one slice of the product design process and only one of many different disciplines that reside under the product design banner. These include but are not limited to: identifying and validating the problem, crafting a user research plan, guiding the product’s information architecture, content strategy, interaction design, visual design, UI design, UX design, and usability testing. Product designers also turn to analytics to gather existing user data or to evaluate how a product performs and make product design adjustments.
Please describe how you test your product designs, what methodologies you use, and how you evaluate product usability.
The fundamental purpose of product testing is to better understand, and empathize with, the core users of a product. User testing—which is part of a user-centered design philosophy—is one of the most important aspects of a designer’s job. A great product designer should talk about the many different types (depending on the project and the design phase) of user tests they employ - from behavioral and attitudinal, to qualitative and quantitative, each with a defined number of participants for optimal results.
Attitudinal and behavioral testing is “what people say” vs. “what people do.” Many times, the two are different. Qualitative and quantitative testing is described as “direct observation” vs. “indirect measurement.” Quantitative testing data will always express a certain quantity, amount, or range, while qualitative testing data contains information about qualities.
They may also talk about moderated user testing and unmoderated remote user testing. Moderated testing is when the tester (usually the product designer) is present and able to guide and observe how a participant is using the product. Unmoderated user testing is when participants are given the test with a set of tasks, and the computer walks them through it, records the session, and collects the data.
Then, there is a product usability evaluation method called a “heuristic evaluation.” A heuristic evaluation identifies a product’s common usability issues so that the problems can be solved, consequently improving the user’s satisfaction and experience and raising the chances of a digital product’s success overall.
Heuristic analysis is an evaluation method in which one or more experts compare a digital product’s design to a list of predefined design principles (commonly referred to as the heuristics) and identify where the product is not following those principles.
A specific set of heuristics contains empirical rules of thumb, best practices, standards, and conventions that have been observed to work over long periods. Sticking to these heuristic standards results in product designs that work more effectively.
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Describe a recent product design project you were particularly challenged by and how you approached the problem.
This question should help you understand more about a product designer’s process. What did they find challenging, and why? How did they set out to come up with a solution? While there is no right or wrong way to approach a particular challenge, having a clear strategy to facilitate an end goal is essential.
For example—on an existing product—did they gather extra user-generated data to help them crystallize a problem? This could mean collecting data using analytics, or it might involve testing the design on a specific demographic in a format that makes the most sense. This could include testing wireframes or interactive prototypes on users to either validate or reject hypotheses, or it could be sending a survey to a broader demographic to better understand product-market fit.
For example, did they employ remote moderated user testing or a form of remote research methodology in order to listen to users and arrive at better design solutions?
Did they interface with C-level executives and company marketing teams to better understand the business goals, their customers, and what the product is trying to solve?
Potentially, a product designer may start multivariate testing or A/B testing and let data lead the way until they hit a roadblock, then continue iterating until they achieve a satisfactory result. Product designers thrive on solving challenges, so a good candidate should readily share enthusiasm about how they approach problems.
One attribute of a great product designer is the ability to evaluate their work objectively. No matter what stage of their career, there will always be those challenges that every product designer strives to overcome in a meaningful way.
Listen for answers that not only describe the challenges they may face but how they overcome them. Also, listen for phrases like OKRs (objectives and key results) and KPIs (key performance indicators), which product designers have to grapple with when evaluating the success of their product designs at the business level.
They may have a challenge justifying their product design process to specific stakeholders—it may seem too costly and take too long. How do they overcome these obstacles? How do they align their work with that of the goals of the business, the company’s brand, and marketing efforts?
For example, convincing a company they need more in-depth user research before a product is designed, or incorporating proper usability testing during a product design lifecycle can be difficult. How do they advocate for those mentioned above in making their case?
Another challenge may be conducting user research in innovative ways. This can prove to be especially tricky for designers who work remotely because direct access to their end users is limited.
Gathering, analyzing, and translating both qualitative and quantitative user data into “actionable insights” may pose another challenge. However, good product designers have a method of focusing on the most impactful elements and teasing out the most significant return on investment.
Listen for answers that include overcoming challenges of working with others with different agendas. A product designer will always face challenges around collaborating with professionals from other disciplines, such as C-level executives, marketing teams, sales teams, growth teams, product managers, engineers, and visual designers.
Follow-up questions on this topic:
- Can you tell me about a time you faced one of these challenges in previous projects and how you went about solving it?
- What were the outcomes of this approach?
Product design is continuously evolving and searching for new ways to solve problems. Seasoned product designers have likely been developing their approach to the design process and will vary from one designer to another. In general, good product designers will walk through a specific process (or “toolkit”) they follow when approaching a problem or project. It will likely be a set of steps they take to solve user problems and create engaging product experiences. Listen for a clear process and a goal to align with business needs and brand promises, a deep curiosity and a constant desire to learn, and the specific steps they take to solve user problems.
One overarching theme should be around a human-centric approach to design; perhaps mention “design thinking,” which follows a thorough understanding of both user and business goals. In general, this is often an iterative design process that is constantly evolving. Key concepts or methods used to carry out this process may include but are not limited to: competitive audits, stakeholder interviews, user personas, empathy maps, user research, content audits, minimum viable product (MVP) and Lean UX, information architecture, business model canvases, mood boards, storyboards, use case scenarios and user flows, customer journeys, wireframes, mockups, prototypes, and usability testing. They may also mention conducting user testing—moderated or unmoderated, remote or in-person—multivariate testing, A/B testing, eye tracking, click-tracking heatmaps, and other quantitative analytics.
Apart from the above, listen for product design methodologies that will help align the product’s design with business goals and marketing and which encompass the company’s brand promise.
By applying these product design methodologies and learning directly from users, each of the techniques mentioned above can play an essential role in the creation of a product that users will love.
Please provide some examples of your experience dealing with HCD (human-centered design).
First and foremost, human-centered design is all about understanding your users. A good product designer will help design products that work well across a variety of use cases across a wide range of audiences, from mobile to desktop, from sites to apps.
A seasoned product designer should be able to elaborate on how they think of and engage user research, which, in essence, drives human-centered design. What “lenses” do they use when conducting user research? These “lenses” could be ethnographic studies, field studies and contextual observations, focus groups, surveys, and diary studies.
Reflecting on past projects, they should mention details of how they set goals for the research and came up with a research plan, how the organizational aspect was approached, the recruiting of representative users—what kind of research questions they asked, and how the results were analyzed. While there is more than one approach to facilitating user research, the designer should have a clear description of the method, the sample size required to gain a meaningful result, and speak to the interpretation of the data.
Look for a product designer who understands how to measure appropriately by selecting the minimum number of subjects needed to gain a strong understanding of the research, and comprehends what they are testing and seeking to understand.
Testing product designs is also a vital aspect of human-centered design. For usability testing, the designer should discuss the methodologies they used. Did they conduct structured, one-on-one interviews with users while they tried specific tasks with product prototypes? Listen for how they’d define a successful test, i.e., what key revelations were gathered and how the data was distilled into practical, actionable insights. Did they use moderated or unmoderated usability testing? (Unmoderated testing examples may include eye-tracking, click-tracking heatmaps, online card sorting exercises, and more.)
Every great product designer has at least a dozen books by design legends on their bookshelf, as well as favorite app designs that they appreciate because of the quality of the user experience.
Listening to the reasons why they love their design heroes and favorite apps can reveal a great deal about a designer’s everyday approach to product design. It will shed light on their “design thinking” sensibility and their bar for quality and will speak volumes about what kind of product designer they are.
It’s more important to listen for the why rather than give credence to names or which design guru it is. Nevertheless, here are a few to take note of: Dieter Rams (German industrial designer at Braun), Steve Jobs and Jonathan Ive (Apple), Don Norman (best known for his books on design, especially The Design of Everyday Things), Steve Krug, and Alan Cooper.
The above also applies to their favorite apps. Again, it’s the why that’s important—listen carefully for what it is in the product’s design that makes these their favorite apps. For example, YouTube, Spotify, SoundCloud, Shazam, Uber, Instagram, Snapseed, and Netflix.
Walk me through a product design example where you set out to solve a business problem.
Using a case study, a great product designer would demonstrate the understanding that they’re not just designing an interface, a website, or an app, but also a way to solve a business problem. First, they would talk about the discovery/problem definition phase, where they carried out comprehensive research to uncover insights into the source of the problem.
Next, keeping business goals in mind, they would have researched users from the target demographic and identified common themes, unmet user needs, and where the business may have fallen short in serving that demographic. They would demonstrate their skill at evaluating the goals of the company, the use case scenarios, and how to best align them to find a solution.
Lastly, they would have reached into their product design toolkit and used wireframes and prototypes (among other things) to explore potential product design solutions. Through user testing, they would have validated ideas and hypotheses focused on obtaining significant business value from the solutions achieved by optimal product design.
Listen for passion and knowledge. A good product designer is going to be excited about this topic; the answer will help you understand where their current focus lies.
Listen for how a product designer keeps up with the industry—such as following design podcasts, reading design blogs and books, attending design conferences, webinars, and online training courses for ongoing learning, and more.
A product designer who thinks ahead will be an invaluable asset to your company. They may talk about new use cases beyond screens—or how designing for accessibility is an area of interest for them. They may discuss new prototyping tools that save developers and designers time by converting the design to code, or may explain an evolving trend and how terrific it is to be at the forefront of technology. Whatever the answer, passion should shine through. Most of all, it’s not about technology; it’s about solving problems for people in new and efficient ways.
Ultimately, it’s not about “design fads.” A great product designer doesn’t follow trends but designs products that have staying power and work well for end users.
Follow-up questions on this topic:
- What would you say the next big product design trend might be?
- What are you most excited about in product design this year?
What is your approach to making websites and platforms accessible to all user groups, including users with visual, hearing, and motor disabilities?
Accessibility is a big topic for product designers, especially as screens begin to shrink, and we consume and engage with digital content wherever we go. Designing digital products that can be used anywhere is paramount to a product’s success. When end users have specific requirements in terms of sensory constraints, the design should facilitate interaction and be even more empathetic.
Take notice if the designer is aware of and follows the World Wide Web Consortium’s ”Web Content Accessibility Guidelines.” Have they performed an accessibility analysis on a previous project?
With a focus on accessibility, user testing becomes especially important and should be comprehensive. An app or a website should be simple enough to facilitate a clear end goal or user task, and innovative approaches should be used to ensure a user with a disability can interact with the product. Some examples could include using voiceover commands to navigate websites and apps for people with motor disabilities, adding captions to a video, which benefits people who are deaf or hard-of-hearing, making content easier to read by screen readers for the blind, or designing an option to use large typography for users with vision impairment.
In that kind of situation, a great product designer exhibits thoughtful restraint. They will not take critique personally but use it as an opportunity to dig deeper and uncover the real reasons why a client may not like a design. Great product designers are objective; they rely on tried and true principles, past learnings, white papers and studies, best practices, standards, and design conventions that have been tested, studied, and validated. Accordingly, they should be able to back up their designs based on those mentioned above.
Typically, in these situations, a misalignment has occurred between what the client was looking for and what the product designer was trying to achieve. A great product designer would take a step back and ask smart questions to uncover the issues a client may have with the design. Is the client subjective as in, “I don’t like that color”? The designer would inquire why and make sure the client understands that design decisions are based on sound principles—color theory, for example—and not subjective opinion.
Also listen for examples of when the product designer backed up design decisions based on analytics data and testing (staying objective) and how they presented facts and findings to make their case.
Some client feedback may be for compelling business reasons. For example, the client may feel that an oversimplified solution misses valuable opportunities for revenue-generating ad placement. A good product designer would listen patiently and incorporate the feedback into the next iteration, understanding that arriving at the optimal design is a balancing act between business needs, technical feasibility, and the designer’s desire to create the best product design.
A great product designer should describe design thinking as a strategy that goes beyond the usual problem-solving focus of most designers. It adds deep empathy for the user of a product to the entire design process, creating a human-centered design outcome. The term “design thinking” is often synonymous with human-centered design (HCD).
Listen for the product designer who describes “design thinking” as a user-centered design process. As Tim Brown, president and CEO of IDEO, a famed global design consultancy, describes it: “Design thinking is a human-centered approach to innovation that draws from the designer’s toolkit to integrate the needs of people, the possibilities of technology, and the requirements for business success.”
Design thinking is a method for the generation of solutions and a practical, creative resolution of problems. It’s about uncovering insights into the unmet needs of your target audience. It’s a form of solution-based or solution-focused thinking, with the intent of producing a constructive future result. Most of all, it’s a “people first” approach—a design process mindset that designs products around people’s needs, motivations, and behaviors.
The design thinking process can be broken down into five stages: empathize, define, ideate, prototype, and test. Each step should be given time and the appropriate resources to create an end product that truly meets user needs and wants.
The answer will help you discover what kind of product designer you may be hiring. While there is no right or wrong answer, a good product designer should have extensive knowledge about the product design process and possess a “design mindset.” Product design is not just about nice-looking screens, it’s about finding the best solutions for the businesses they serve and the end users.
A great product designer would talk about what a “design mindset” means, a comprehensive, holistic, end-to-end product design process, approaches, and methodologies. They should be willing to walk step by step through an ideal product design approach they consider essential to excellent product design and that guides them to robust working solutions.
Listen for humility backed by confidence. Do they have a cultivated eye for solutions? Are they passionate about creating delightful user experiences and designing products people love?
Listen for answers that include a discussion around empathy—things like “walking a mile in a customer’s shoes” (customer journeys) and a human-centered, goal-driven approach to designing products. Empathizing with people often means engaging in in-depth user research to solve problems. At the core of a design mindset is the ability to empathize, together with the ability to formulate great questions. It’s essential to ask the right questions in order to come up with reliable solutions; and to ask great questions, designers need to be able to empathize with people and gather relevant information through in-depth research.
A seasoned, experienced product designer balances business goals and technical constraints with creating the best user experience possible. They should come up with “personas” (the core users of a product), define when and how to do surveys, distill research findings, conduct field visits and interviews, report their research findings, create wireframes and prototypes, conduct usability testing, and, in order to make further improvements, analyze quantitative user data once a product is released.
There is more to interviewing than tricky technical questions, so these are intended merely as a guide. Not every “A” candidate worth hiring will be able to answer them all, nor does answering them all guarantee an “A” candidate. At the end of the day, hiring remains an art, a science — and a lot of work.
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Marti is a senior UI/UX designer based in New York. For the past several years, he's been designing digital products for the banking, hospitality, fashion, healthcare, pharmaceutical, automotive, and software industries. Marti's past clients include Citibank, HP, Galaxkey, Meta, Deutsche Bank, Volkswagen Group, Riyad Bank, Vorwerk Thermomix, Asics, The Ritz-Carlton Group, Hilton Hotels & Resorts, Al Rajhi Bank, and First Abu Dhabi Bank.Show More
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