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Interview guide for product designers

How to nail your product design interview

Written by Robyn Luyt
Updated today

Your design assessment is less about creating a beautiful design and more about articulating your decisions and justifying your solutions with evidence. Your portfolio review is a critical opportunity to control the narrative.

1. The Portfolio Review: Control the Conversation

When presenting your portfolio, your job is to lead them through your thought process, not just scroll through mockups. Remember, this might be the first time the interviewer is seeing your work.

Set the Stage:

  • Align first: Start by asking the interviewer if they have a preference on how to proceed (e.g., chronological order, focus on specific skills or specific parts).

  • Prioritise Impact: Focus on your best and most relevant projects first, typically those highlighted or listed earliest on your website.

  • Cover the Essentials: Every project discussion should quickly cover:

  • Identifying the problem domain: Clearly define the core challenge and goal you were addressing.

  • State the approach: Briefly introduce your/your team’s methodology (e.g., lean, user-centred, iterative).

  • Introduce the solution: Give a brief high-level introduction to your solution before going into the step-by-step details.

  • Justify the design: Walk through the steps, explaining why you made specific choices

  • Anticipate the Tough Questions: Be ready to answer questions that demonstrate reflection and growth

  • What constraints, obstacles or hardships did you encounter?

    How did you navigate them?

  • What trade-offs did you make? (e.g., speed vs. accessibility)?

  • What would you do differently if you had more time or could revisit the project today?

2. Master the Behavioural Q&A (The STARE Method)

When asked about challenges, use the STARE method to demonstrate not just your craft, but your ability to measure and refine your design decisions.

Example: Handling Stakeholder Conflict

  • S – Situation: "On the Pick ‘n Pay project, the lead developer flagged that my proposed checkout animation would add two weeks to the sprint, threatening our launch date."

  • T – Task: "I needed to maintain the premium brand feel and user guidance of the animation without delaying the engineering timeline."

  • A – Action: "I facilitated a 'trade-off' meeting. Instead of insisting on the original vision, I performed a functional audit of the motion. I stripped the animation to its core purpose, feedback, and implemented it using native CSS transitions rather than a heavy third-party library."

  • R – Result: "We launched on time with zero bugs in the checkout flow. Post-launch usability testing showed a 15% increase in 'perceived speed' by users."

  • E – Evaluation: "Looking back, I realized I hadn't consulted Engineering during the high-fidelity wireframing phase. I’ve since adjusted my workflow to include technical feasibility check-ins earlier in the design sprint to prevent late-stage rework."

3. The Case Study: Building a Bulletproof Argument

A case study is your strongest piece of evidence. Your goal is to move beyond describing what you did and focus on why, what happened, and what you learned

Set the Hook (Overview & Title)

  • Be Specific: Ensure your project title gives immediate context and isn't too generic.

  • Bad Example: Pick ‘n Pay Depot

  • Good Example: Pick ‘n Pay user research for mobile app checkout

  • State the Goal: Quickly define the problem and the high-level objective of the project.

The Argument (The Process Section)

This is where you dedicate the bulk of your effort.

Frame this like a science experiment report by addressing these four questions for every major step:

Question

Designer Focus (The Evidence)

What did you do?

State the action clearly

Example: Relied on usage metrics and 8 usability tests

Why did you do it?

Explain the rationale

Example: To gain a deeper understanding by combining qualitative and quantitative information.

What was the result?

Document the immediate outcome

Example: Users were quicker overall, but continued to struggle with the shipping section.

What did you learn?

Share the key insight gained

Example: Discussions revealed that products in one order often have different shipping addresses, which was possible but difficult in the current checkout.

The Summary (Headlines & Outcomes)

Conclude your case study by summarising the impact, not just the features.

  • Use Headlines to Summarise: Pretend you have to summarise your entire case study in a few impactful sentences or “tweets”. These highlights become your key headlines.

    • Goal: If a person only skimmed these, they should still understand the main points and outcomes.

  • Document Outcomes: Clearly document the impact.

    • Document the metrics and include the lessons learned as part of the outcome.

4. Competency Spotlight: How to Talk About Design Skills

Focus on showing how your skills solve business problems and support your decisions with clear evidence from your projects.

Skill to Discuss

The "Money" Quote to Use

Your Evidence Checklist

UX Research

"We identified our target users and gathered data to ensure we made informed design decisions."

Analytical Research (personas, data gathering) and User Testing (wireframe/prototype testing, card sorting, heatmaps).

Wireframing

"I aimed to drive conversation about the experience I was creating, not the execution or visual appeal."

Show simple, low-fidelity frames and explain how they prevented debates about how your wireframes look.

Information Architecture

"My focus on IA ensures the content is logical and within reach; otherwise, even an awesome feature is moot if users can't find it."

Organisation systems (hierarchical/sequential), labelling systems, and navigation systems.

UI Design Systems

"The Style Guide isn't just for consistency; it serves as the instruction manual for the frontend development team to ensure a uniform, intuitive interface."

Moodboards, colour palettes, icons, buttons, dropdowns, and complex elements.

Prototyping

"I used prototyping to test assumptions derived from research and catch mistakes before expensive coding fixes were needed."

Show how prototyping helped secure buy-in from stakeholders or validate key functionality.

Visual Communication

"I focus on visual hierarchy and making elements look clickable, minimising the need for written instructions."

Discuss visual design principles (typography, colour, shape).

Interaction Design

"By analysing mental models and competitor products, I knew users expected to scroll rather than swipe through that specific list."

Competitor analysis, observing user product usage.

Web Development

"My knowledge of HTML/CSS eases the design-developer handoff and helps me understand what's technologically possible."

Mention languages/frameworks like HTML, CSS, JavaScript, and jQuery.

5. Extra Credit: The Microcopy Edge

Remember, Microcopy (the perfectly crafted words in your app, like button labels, error messages, and tooltips) is a powerful tool to create a good user experience.

  • Integration: Mention the intentional language chosen in your designs

  • Impact: Explain how your UX writing speaks to your users’ mental models and helps them understand your product better.

Additional Resources:

  • Your design assessment is less about creating a beautiful design and more about articulating your decisions and justifying your solutions with evidence. Your portfolio review is a critical opportunity to control the narrative.

    1. The Portfolio Review: Control the Conversation

    When presenting your portfolio, your job is to lead them through your thought process, not just scroll through mockups. Remember, this might be the first time the interviewer is seeing your work.

    Set the Stage:

    • Align first: Start by asking the interviewer if they have a preference on how to proceed (e.g., chronological order, focus on specific skills or specific parts).

    • Prioritise Impact: Focus on your best and most relevant projects first, typically those highlighted or listed earliest on your website.

    • Cover the Essentials: Every project discussion should quickly cover:

    • Identifying the problem domain: Clearly define the core challenge and goal you were addressing.

    • State the approach: Briefly introduce your/your team’s methodology (e.g., lean, user-centred, iterative).

    • Introduce the solution: Give a brief high-level introduction to your solution before going into the step-by-step details.

    • Justify the design: Walk through the steps, explaining why you made specific choices

    • Anticipate the Tough Questions: Be ready to answer questions that demonstrate reflection and growth

    • What constraints, obstacles or hardships did you encounter?

    • How did you navigate them?

    • What trade-offs did you make? (e.g., speed vs. accessibility)?

    • What would you do differently if you had more time or could revisit the project today?

    2. Master the Behavioural Q&A (The STARE Method)

    When asked about challenges, use the STARE method to demonstrate not just your craft, but your ability to measure and refine your design decisions.

    Example: Handling Stakeholder Conflict

    • S – Situation: "On the Pick ‘n Pay project, the lead developer flagged that my proposed checkout animation would add two weeks to the sprint, threatening our launch date."

    • T – Task: "I needed to maintain the premium brand feel and user guidance of the animation without delaying the engineering timeline."

    • A – Action: "I facilitated a 'trade-off' meeting. Instead of insisting on the original vision, I performed a functional audit of the motion. I stripped the animation to its core purpose, feedback, and implemented it using native CSS transitions rather than a heavy third-party library."

    • R – Result: "We launched on time with zero bugs in the checkout flow. Post-launch usability testing showed a 15% increase in 'perceived speed' by users."

    • E – Evaluation: "Looking back, I realized I hadn't consulted Engineering during the high-fidelity wireframing phase. I’ve since adjusted my workflow to include technical feasibility check-ins earlier in the design sprint to prevent late-stage rework."

    3. The Case Study: Building a Bulletproof Argument

    A case study is your strongest piece of evidence. Your goal is to move beyond describing what you did and focus on why, what happened, and what you learned

    Set the Hook (Overview & Title)

    • Be Specific: Ensure your project title gives immediate context and isn't too generic.

    • Bad Example: Pick ‘n Pay Depot

    • Good Example: Pick ‘n Pay user research for mobile app checkout

    • State the Goal: Quickly define the problem and the high-level objective of the project.

    The Argument (The Process Section)

    This is where you dedicate the bulk of your effort.

    Frame this like a science experiment report by addressing these four questions for every major step:

Question

Designer Focus (The Evidence)

What did you do?

State the action clearly

Example: Relied on usage metrics and 8 usability tests

Why did you do it?

Explain the rationale

Example: To gain a deeper understanding by combining qualitative and quantitative information.

What was the result?

Document the immediate outcome

Example: Users were quicker overall, but continued to struggle with the shipping section.

What did you learn?

Share the key insight gained

Example: Discussions revealed that products in one order often have different shipping addresses, which was possible but difficult in the current checkout.

The Summary (Headlines & Outcomes)

Conclude your case study by summarising the impact, not just the features.

  • Use Headlines to Summarise: Pretend you have to summarise your entire case study in a few impactful sentences or “tweets”. These highlights become your key headlines.

    • Goal: If a person only skimmed these, they should still understand the main points and outcomes.

  • Document Outcomes: Clearly document the impact.

    • Document the metrics and include the lessons learned as part of the outcome.

4. Competency Spotlight: How to Talk About Design Skills

Focus on showing how your skills solve business problems and support your decisions with clear evidence from your projects.

Skill to Discuss

The "Money" Quote to Use

Your Evidence Checklist

UX Research

"We identified our target users and gathered data to ensure we made informed design decisions."

Analytical Research (personas, data gathering) and User Testing (wireframe/prototype testing, card sorting, heatmaps).

Wireframing

"I aimed to drive conversation about the experience I was creating, not the execution or visual appeal."

Show simple, low-fidelity frames and explain how they prevented debates about how your wireframes look.

Information Architecture

"My focus on IA ensures the content is logical and within reach; otherwise, even an awesome feature is moot if users can't find it."

Organisation systems (hierarchical/sequential), labelling systems, and navigation systems.

UI Design Systems

"The Style Guide isn't just for consistency; it serves as the instruction manual for the frontend development team to ensure a uniform, intuitive interface."

Moodboards, colour palettes, icons, buttons, dropdowns, and complex elements.

Prototyping

"I used prototyping to test assumptions derived from research and catch mistakes before expensive coding fixes were needed."

Show how prototyping helped secure buy-in from stakeholders or validate key functionality.

Visual Communication

"I focus on visual hierarchy and making elements look clickable, minimising the need for written instructions."

Discuss visual design principles (typography, colour, shape).

Interaction Design

"By analysing mental models and competitor products, I knew users expected to scroll rather than swipe through that specific list."

Competitor analysis, observing user product usage.

Web Development

"My knowledge of HTML/CSS eases the design-developer handoff and helps me understand what's technologically possible."

Mention languages/frameworks like HTML, CSS, JavaScript, and jQuery.

5. Extra Credit: The Microcopy Edge

Remember, Microcopy (the perfectly crafted words in your app, like button labels, error messages, and tooltips) is a powerful tool to create a good user experience.

  • Integration: Mention the intentional language chosen in your designs

  • Impact: Explain how your UX writing speaks to your users’ mental models and helps them understand your product better.

Additional Resources:

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