At my work I regularly interviewed managers of various levels – from interns to CPO-level people, and conducted mock interviews. Recently, I went through interviews by myself at Google and other companies and received an offer from one big company in the Middle East. In this article, I will share my experience and give some tips how to prepare for a product interview.

The Product Sense Interview or Product Design Interview is an important stage in the interview process for a product manager role. It tests your work experience, the depth of your practical knowledge, and how clearly you can communicate what you know. You need to prepare for all sections, but I would recommend to pay special attention to this one, since this is a key stage of evaluating your product skills.

Types of cases

Create a product from scratch

Example questions – Design a refrigerator for children, Design a taxi service for elder people, Design a vending machine for hotels. These questions may seem too academic, but they are really asked in interviews. For example, I was asked the last question in an interview at Google.

Improve an existing product

Example questions – Imagine that you are a product manager at Google Search and your task is to improve it, how will you act? This is a case that I always give in my interviews, substituting the product that I am currently working on.

Both types of questions can be prepared for using a similar approach.

How to prepare

Step 1. What to read

There are two good books for preparing for interviews that have already become industry standards, and they really help prepare well, not only for product interviews, but also for other types of questions that you will be asked.

• Cracking PM Interview

  I used this book to prepare for interviews at Yandex six years ago. And it's still relevant, I recommend it to all my mentees. It's suitable for any level – both for those who don't know where to start learning the profession of a product manager, and for those who have already advanced in the profession. This book is good because it provides an overview of all the domains that managers need to know, and therefore all the types of questions that need to be prepared. It provides solutions with a clear structure.

• Decode & Conquer

  It takes second place in my rating and rather complements the first book. It also provides cases with solutions, but it largely duplicates Cracking PM Interview and provides a more complex structure for solving cases, but it's still useful as an additional resource.

Step 2. What to watch

Watch how other managers go through interviews. You can find many examples on YouTube by searching for Product Design Interview Mockup. For example, here and here.

Step 3. Prepare a template for your answer

After reading books and watching different interviews, create your own template for your answer, write it down on a piece of paper and keep it handy during the interview, like a cheat sheet. This will help you not to get lost in your thoughts and remember the aspects that need to be covered in your answer.

Here is the template I use:

1. Goals (why)
2. Metrics
3. Constraints (deadline, resources, platforms, geo)
4. Users Groups (who, why do they need it, choose one group)
5. CJM & pain points
6. Prioritise (reach, impact, confident, effort)
7. List solutions
8. Evaluate solutions (trade-off & risks)
9. Describe your product (sum-up)

Step 4. Take a few interviews in advance

To avoid being too nervous during real interviews, practice them in advance. The easiest way is to take one of the questions and record a zoom call with yourself, then watch it and analyze the mistakes. More effective is to find a mentor and work through the product section with him, so you will get feedback faster. I recommend taking a few interviews with different people and see what they pay attention to. Hiring managers are very different, it is useful to listen to several opinions in order to better prepare.

Tips, what you can’t find in books

Before drafting a solution, answer the question “Why?”

I always try to think about any product from two sides – why does the business need it and why do the users need it. This also helps in solving cases. The answers to these questions influence the solutions that should be offered. For example, a business may have a main goal of increasing revenue, or it may be growth and retention of the audience. Depending on the goal, the solutions will be different.

Make your answer easy to follow

A pre-prepared answer plan will help you with this. Some candidates share the screen and sketch out the structure of their answer in real-time. This is great for helping the interviewer follow your thoughts. But this is not always convenient, for example, I type slowly in English, and writing the structure takes time, of which there is not much time during an interview. Therefore, I use another approach. During my response, I try not only to answer the question, but also to tell the plan of my answer upfront, and summarize it at the end. This rule is used in presentations: 1) tell what you are going to say, 2) say it, 3) summarize what you just talked about.

Conduct a dialogue

A case is not a monologue, it is also designed to demonstrate your communication, cooperation and teamwork skills. Ask clarifying questions, periodically check whether you are on the right track in your solution. But do not try to force the interviewer to solve the case for you. It is normal to ask whether what you are proposing makes sense and whether it is possible to move on to the next stage, but you should not ask what possible solutions exist.

Distribute your time properly

Typically, an interview lasts 45 minutes, of which five are spent on greeting and a short introduction, and another five at the end on questions about the position you are interviewing for. There are 35 minutes left to solve the case. It’s important to distribute this time properly. From several user groups, it is better to choose one and focus on it. Then identify several problems that this group faces and choose one again. But it is better to offer several solutions. This way you will increase the probability that one of them will be good and will be able to demonstrate prioritization skills. When choosing one of the user groups and one problem, it is better to explain why you decided to focus on it. For example, it could be the largest group or the one that brings in the most revenue.

Common mistakes

Let me share some common mistakes that I've encountered in my practice.

Jump straight to solutions

The most common mistake is to jump straight to sketching out ideas. A candidate is asked to improve a product, they open a website or application and starts listing ideas – add a filter here, and a button there. This is a 100% no hire, because it is unlikely that a candidate will be able to come up with something brilliant right away, without knowledge of the product, audience and business goals, rather he will demonstrate a lack of experience.

Think that deep expertise in the product is necessary

In fact, it doesn't matter what kind of product you are creating or improving – a delivery application, a vending machine or Google search. In solving a case, it is important to show that you know the product approach and no matter what service you are working on, you know where to start.

Follow templates too literally

Once, I failed an interview because I followed a prepared template too literally instead of solving a case from my head. Solving a case requires not only formally going through all the steps from the template, but also the ability to rely on your own experience and adapt to changing task conditions on the fly. Therefore, it makes sense to solve several cases in advance to practice all the skills together.

Conclusion

It’s important to be prepared for all interviews, but I would pay special attention to the Product Sense Interview, as this is a key stage, where a product manager can demonstrate their skills. To be well-prepared, I would recommend reading Cracking PM Interview, watching videos of others going through the interview on YouTube and taking few mock interviews in advance. Also it’s important to prepare your own template for an answer and know some common mistakes that candidates often make. I hope this article helps you in your preparation, and wish you success in your interviews. I’m also curious about the challenges you’ve faced during the interview process, and what things helped you went through the product case interview.