A product manager's core responsibilities include working with a team to design, build, ship, and continuously improve a product. During product manager interviews, most companies love to hone in on your ability to execute against these responsibilities by asking how you might think about designing a product.
The popular product design question usually takes form in something like:
"Walk me through how you would design X product for Y user"
Some common example questions we've frequently heard include:
- Design a pen for an astronaut
- Design an alarm clock for a blind person
- Design an elevator for an individual in a wheelchair
When you answer these types of product design questions as part of the product manager interview, you should always approach them with a framework in mind. Below is one that we highly recommend:
The Product Design Interview Framework
1) Ask Clarifying Questions
Remember, there is no point continuing with an answer if you haven't fully grasped the situation.
I can't count the of times I've asked a simple product design question to a candidate who then proceeded to give me a lengthy five minute answer before I realized that the candidate had never used the product before.
If I asked a candidate to walk me through how he/she might design a better wallet, I expect the candidate to first ask clarifying questions such as who the wallet might be used by, or what "better" means in the context of a wallet.
Remember, product managers don't just dive headfirst into launching a product without first understanding the whole situation and the business goals.
A candidate who doesn't ask clarifying questions is a big red flag and tells me that he/she would design products without understanding what a user truly needs.
2) Communicate Your Answer Outline
There is nothing worse for an interviewer than trying to follow a candidate's unstructured train of thought when responding to a product question.
It's crucial to demonstrate that you have taken time to comprehend the situation and then lay out some groundwork on how you plan to answer this question.
Showing that you are organized by structuring out your answers to these questions will put your interviewer at ease and keep your thoughts in line so that you don't ramble or go off on tangents.
An example of how you might approach this is to say "Now that I've understood the scope of this product, I'd like to lay out how I might approach this design question.
First, I'm going to re-iterate what my business goals are.
Second, I'll identify my customer base and their use cases.
Third, I'm going to brainstorm some features and evaluate these features against the business goals I've listed.
Lastly, I'll discuss trade-offs and summarize my recommendation."
3) Identify the Users / Customers and their Use Cases
Although you might have lightly touched upon this while asking some clarifying questions, this step is crucial to locking down exactly who the product's customers and users are and their use cases. Remember that for certain products, the customer and the user of the product may be different people. For example, in the educational app/games market, parents are often the customers who buy these apps / games for their children to use.
I would recommend drawing a 2-column table on a whiteboard or piece of paper with: your users/customers on the left column, and their respective use cases on the right column (users/customers may each have multiple use cases so leave some room on the right side to account for that).
For example, going back to the better wallet, a user might be a working adult who uses a wallet to store their cash and critical cards (i.e. license, debit/credit cards/business cards).
At this point, it would be great to ask more clarifying questions to your interviewer about whether or not they want to focus on a particular user/customer to save time.
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4) Identify Gaps in the Use Cases
Now that you've compiled a list of various use cases, it's time to thinking about how current products/solutions in the market address these use cases and whether or not there are any gaps or room for improvement.
Taking a step back, it's good to look down your left column of users/customers and think about the qualities that are special to each one of them.
Like a true product manager / customer advocate, put yourself in their shoes and think about their limitations and values.
This will help you to better identify weak spots in current product offerings. If you want, you can add a third column next to each use case to help structure the obvious gaps that you identify.
5) Brainstorm Features / Improvements
Now that you've figured out the gaps that current products are missing to address user/customer needs, it's time to break out that thinking cap and brainstorm solutions to address these gaps.
Make sure that your features / improvements match the use cases that you've listed. Don't be afraid to ask your interviewer if you are on the right track or if they prefer you to focus on one or two of your ideas.
6) Prioritize and Identify Trade-offs
With this shiny list of brainstormed features and improvements, it's time to prioritize which of these you might focus on and what the trade-offs would be with each solution.
When you prioritize your ideas, it's important to use some sort of decision framework. If you are focusing on business goals like revenue, it might be important to evaluate each feature by the ratio of potential revenue generated vs. the time & cost it would take to develop.
One simple way is to take the (potential revenue generated - cost to develop ) / time to develop and sorting your list from top-down values.
Once you've come up with this list, think about the pros/cons and trade-offs of choosing to implement each solution. This lets you automatically play devil's advocate to your own ideas to show your interviewer that you are thinking about all facets of the solution including edge cases and potential negatives.
As an interviewer, I love to see candidates critically think about their own ideas and tell me the trade-offs proactively.
7) Summarize your Recommendation
Whew, you're almost done with your product manager interview. Let your interviewer know what your final choice is and feel free to review how you came to the solution and why it satisfies a user/customer's needs.
If you haven't elaborated enough already, feel free to reiterate why you chose this solution over the others on your brainstormed list.
Congratulations, you've finished your first product design question.
Interested in learning how to dominate these types of product manager interview questions and land the product manager job? You might want to check out our popular course: One Week PM.
Clement Kao is a Co-Founder of Product Manager HQ. He is currently a Product Manager at Blend, an enterprise technology company that is inventing a simpler and more transparent consumer lending experience while ensuring broader access for all types of borrowers.