How to Ace the 7 Types of Product Case Interview QuestionsApr 18, 2023
Product case interviews can be one of the scariest parts of the data science interview process. That’s largely because the questions are open-ended. There’s no one correct answer, and that’s intimidating for a lot of candidates, even experienced ones. You will need to demonstrate not that you have memorized answers but that you have high critical thinking and problem-solving skills.
In this blog, my goal is to take the fear out of product case interviews. We’re going to look at 7 different categories of product case interview questions which will help you know better what to expect and how to prepare.
If you prefer to get this information from a video, you can head over to my YouTube channel for that.
Now, let’s dive in!
What Exactly Is a Product Case Interview?
Before we get into the different types of questions, you can expect in a product case interview, let’s first clarify what exactly a product case interview is.
You may have heard these interviews referred to as business case, business acumen, product interpretation, or metric interviews as well. Different companies call it by different names, but they all point to the same type of interview.
A product case interview tests your ability to make suggestions and solve problems for business scenarios. These scenarios tend to be about a company’s products or features. Here are some example questions:
- What are the pros and cons of using Daily Active Users as a success metric?
- How would you investigate a negative metric shift in time spent on the app?
- How would you design an experiment to test a new feature?
- If an A/B test shows that the desired metric (eg. Click Through Rate) is going up while another metric (eg. Clicks) is decreasing, how would you go about making a launch decision?
You could find yourself encountering these questions both on phone screens and in onsite interviews. If you are interviewing for a product data scientist position, expect to encounter at least one round of product case interviews.
7 Types of Product Case Questions
As you can see from those sample questions, product case questions are open-ended and can be quite broad. This creates two challenges for you when answering. First, knowing exactly what to say is hard because there are so many possible ways to approach the question, and second, it can be tricky to stay organized when answering open ended questions.
In other words, how do you know what to say and how do you make sure it makes sense?
Although it’s not possible to prepare an answer for every question you might get in advance, it is possible to have a general approach for different types of questions. If you have an idea of what types of questions you are likely to get, you can study more effectively and walk into interviews more confidently.
How do you know what questions you are likely to get though?
Luckily, I’ve done the hard part of figuring that out for you. I analyzed over 360 interview questions from 46 different companies (including places like Uber, Doordash, Lyft, Amazon, etc.) and divided those questions into 7 categories. I call this the data-driven approach to product case interviews.
So, why is this chart helpful?
A breakdown like this shows you exactly what you need to study for the most coverage. By starting your preparation with the largest category (Measure Success) and working your way down to the smallest (Estimation), you can be sure of achieving the most coverage of interview questions in the least amount of time.
When you know what to expect, you know how to prepare and what to practice so that even product case questions don’t catch you off guard. Now, let’s take a closer look at each category of question. We will examine what each category is and some tips for answering those types of questions.
Measure Success (~23%)
These questions ask you to measure the success of a product or feature, and they account for around 23% of questions you are likely to get in product case interviews. Some example questions are:
- How would you measure the success of YouTube's Story feature? What metrics would you look at to see if it's doing well?
- If Uber is planning to launch a referral program for riders, what metrics would you use to measure its success?
How do you approach this type of question?
The key here is to identify helpful metrics. Looking at things like user engagement, conversion rates, and retention can tell you if a feature is resonating with users. If the question is about launching a new feature, you should focus on metrics that can tell you the potential impact of the new feature.
To select the best metrics for measuring success, it’s also important to consider the pros and cons of each metric. While individual metrics are helpful they often don’t show the full picture, which is why using a combination of metrics typically gives you a better understanding of overall product success.
These questions help interviewers determine if you can help the business make informed decisions. By picking the right metrics, you show that you know how to gain valuable insights into the effectiveness of different features and products.
A/B Testing (~22%)
A/B testing questions ask you to design an experiment and make suggestions based on the result. Here are some examples:
- How would you set up an experiment to test a new feature in Quora?
- If engagement decreased in one segment but increased in others, how would you decide whether or not to launch a feature change?
- What changes would you make to the Tiktok app? How would you test if the proposed change is effective or not?
There are two different ways you might encounter this question. You will either be given an idea and asked to design an experiment to test it, or you will have to come up with an idea first and then design an experiment to test. Coming up with your own idea first is challenging, but it also gives you more opportunity to show your creativity and problem-solving skills.
Regardless, A/B testing questions require you to think through the different components of designing a test, considering and addressing any potential challenges as you do so. You will also need to analyze the results and make informed suggestions based on the data. It can be helpful to look at things like driver metrics, guardrail metrics, and cost to determine whether the idea would be effective.
Diagnose a Problem (~18%)
These questions are all about problem-solving. They ask you to figure out what is causing an issue. Example questions include:
- The estimated arrival of Lyft or Uber rides has increased by 3 minutes. How would you determine what is causing this?
- How would you investigate a 1% drop in daily active users on Slack?
- A referral program at Doordash isn’t generating the expected response rate. How would you investigate the issue?
There are a lot of different things that can cause problems like this, so having a structure to approach this type of problem is essential. You need to know what factors you would investigate first and what factors you would look at later.
The exact order of investigation will depend on the question. Investigating systematically means prioritizing factors based on their potential impact. You should start with the thing that is most likely to be the cause and systematically work through investigating other factors until you find the issue.
In the previous 3 categories the questions you’re likely to encounter in a product case interview. That gives you pretty great coverage already, so if your time is limited you want to focus on those. However, there is still the remaining 40%, which we will touch on briefly here.
Product-specific questions are the catchall category. It refers to questions that are so specific to particular companies' products or features that similar questions would not be asked at another company. Some examples are:
- How do you evaluate the impact of fake news on Facebook?
- How do you determine the optimal ratio between company posts and individual posts for LinkedIn feeds?
Because there are unique to particular companies, these questions require a deep understanding of a company’s products and industry. It’s important to do your research and make sure you thoroughly understand what a company does and what types of market it operates in before showing up for the interview.
Improve a Product (~10%)
These questions really evaluate your ability to think creatively. They ask you to come up with ideas to improve a product. Example questions include:
- How would you improve user engagement on LinkedIn?
- How would you improve TikTok and what new features would you add to it?
- How would you improve "What's on your mind" posting on Facebook?
These questions give you a chance to show that you can come up with practical solutions to complex problems. They can be intimidating, but they are an excellent chance to show that you can think outside the box and contribute your powerful perspective to the company.
Strategic Thinking (~6%)
Strategic thinking questions require you to analyze complex scenarios and make informed decisions that have a long-term impact on a product or company. They test your ability to consider the bigger picture. Here are some examples:
- Back in 2016, there was no "story" feature on Instagram. How do we decide whether to launch this feature or not?
- What should the hourly rate for Instacart shoppers be?
To answer these well, you’ll need the ability to step back and consider the implications of your decisions. It involves thinking beyond the company even to the overall market and competition. You will have to assess things like risks and benefits and create a plan that balances short-term and long-term goals.
In short, these questions are difficult, but they really highlight that you can have a meaningful impact on a business.
This last question category is more often used by banks and consulting firms than tech companies. It asks you to make quick calculations based on limited information. An example question would be:
- Calculate the profit for a credit card partnership, based on existing users, revenue, cost, and potential joint marketing campaigns.
To answer this, you need to be able to think quickly and be comfortable with numbers and basic financial concepts. You also have to be able to quickly grasp context and identify key information. It’s all about showing that you can think on your feet.
By knowing these 7 categories of questions, you can walk into product case interviews better prepared and ready to succeed. Knowing what to expect can help you practice and prepare more effectively so that you can answer even open-ended questions with clear structure and great ideas.
If you want even more help with your preparation for product case interviews, I highly recommend checking out my product case interview cheat sheet which you can download for free. The sheet covers all the categories discussed in this post and more! If you found this post helpful, be sure to check it out.