PM Quest learning library

How to Approach Product Design Cases

A practical guide to approaching product design PM cases.

Product Design Cases

Product design cases ask you to reason through a user need and shape a focused product approach. A typical case might be: “How would you build an interview preparation tool for LinkedIn?”

These cases ask you to build or improve features for a target segment. Even though it is called product design, you are not really supposed to “design” anything using a tool.

You must be thinking, “If I am not supposed to design, what am I supposed to do?”

Before we go into that, let’s talk about the “why” behind this case type.

What good product thinking looks like

Strong product design cases test whether you can show:

  1. Empathy - Can you think about customers, their needs and wants, and really be in the shoes of the customer?
  2. Design Thinking - Can you evaluate how well designed a product is? What are the ways in which a product is well designed and what are some gaps?
  3. Product curiosity - Can you show that you care about how products work in the real world?

Cool, now we understand what this case type is trying to assess. Let’s move on to how you will work through the product design problem.

Product Design Process

A simple but very effective framework for product design cases focuses on the users: Who are they? What do they need? How can we address that need?

We can also think of this in the terms of the Design Thinking framework.

Design thinking basically has 5 steps. We can walk through any product design case while following these steps:

  1. Ask clarifying questions
    1. The purpose of asking clarifying questions is two-fold. These questions can help you:
      1. Understand the problem you are supposed to solve
      2. Buy time to think about how to approach the case
    2. Your clarifying questions will vary based on the case so I won’t list too many.
    3. Examples of clarifying questions:
      • Why are we doing X? What does the company want to achieve through this?
      • Who is this for? Why would they use it?
      • Who am I in this situation? Google PM? New startup?
    4. Don’t ask more than two or three clarifying questions. The goal is to see that you can make decisions based on logical assumptions, so be prepared to answer your own questions.
  2. Empathize - Identify the users
    1. “Who is my user?”, “What matters to this person?”
    2. Learn about the audience for whom you are designing. With any product case, the first step is always to identify the users.
    3. No matter how simple the question seems to be, start by clearly defining who you think the main user group is. It's fine if you think there are several core user groups - call them out!
    4. For a lot of product design cases, it's fine to have a broad user group. Perhaps it's "millennials" or perhaps it's "people who shop online". It could be interest-focused, like "people who like to explore new restaurants".
    5. The user group can be defined by any number of factors, such as demographics, profession, background, experiences, or interest.
  3. Define - Identify relevant user needs
    1. “What are the user needs and product goals?”
    2. Once you've declared the target user, identify the problem they have.
    3. Remember that, when discussing a product, there's usually one or a couple main pain points as well as adjacent needs the target users may have.
    4. Discuss the various use cases for the users and prioritize to focus on one of them.
  4. Ideate - Identify product solutions
    1. Brainstorm and come up with as many solutions as you can for the problem.
    2. If you're analyzing an established product, chances are that it does solve the needs of its target audience(s) - that's what keeps it in business. But, users' needs are rarely solved 100% of the time, so you should think about ways the product could improve.
    3. Don't be afraid to describe in plain language why you think a product fulfills the user's need well, even if it seems relatively obvious. It’s fine to come up with only an incremental change.
    4. The most important thing to do is to tie everything back to the target users and their needs. This sounds simple, but it's easy to forget in the heat of the moment.
    5. At this stage, it's less about having a "right" answer and more about showing how much you think and care about the user and can come up with ideas to solve those problems.

This basic framework will get you pretty far with a product design case. Often, there are next steps which would strengthen your approach.

  1. You might be asked to draw some wireframes to communicate your solution visually.
  2. One extension goes into product metrics. Given the user, user need and product, how do we know quantitatively how well the product solves the need? Continue with the metrics definition case guide.
  3. Another direction is the competitive landscape: Is there a product that does something similar? How well does it solve the user need? How can your product differentiate itself? You can also discuss business considerations such as distribution, trust, operational cost, or monetization.

Product design cases can have a wide scope, but the basics always come down to the same thing - identify the target user, their needs, and what does (or doesn't) fulfill those needs. Think like a PM.

A concise answer structure

Open with the company objective and constraints. Segment users using behavior or needs, select one segment, and explain why it matters. Prioritize one painful and frequent job, generate several distinct solutions, and choose an MVP based on impact, risk, and feasibility. Walk through the critical user journey, including trust and failure states, then define an outcome metric and guardrails.

Avoid spending the entire interview brainstorming features. The strongest signal is a chain of reasoning from goal → user → need → solution → trade-off → measurement.