StellarPeers is a community platform that helps professionals prepare for interviews. We think the best way to prepare, is to work through questions and practice mock interviews as much as possible. We meet weekly to discuss product management interview questions on product design, product launch, strategy, marketing, pricing, and others. Last week, we worked on a product design question.
What is this question about?
This product management interview question tests whether you understand the process of going from customer needs to product development. This process involves determining who the customer is, understanding what they want to accomplish, defining multiple use case scenarios, prioritizing what to build, and having good business acumen.
What is the interviewer looking for?
The interviewer is evaluating you on the following:
- Can you empathize with customers? Can you articulate their needs, feelings, and expectations?
- Are you able to provide multiple and diverse use case scenarios?
- Is your answer structured and logical, or do you ramble?
- Do you go beyond generalities in your solutions and provide detailed descriptions?
- Can you provide ideas that no other candidate has mentioned?
- Are you confident and sound credible? Would engineers and other team members follow your lead?
How to structure your answer?
Here is a suggestion on how to structure your answer:
- Ask Clarifying questions: Understand the question being asked and narrow the scope.
- Business Goal: What is the business goal of building this new product? For example, it could be to diversify revenue, increase sales volume, increase retention, etc. If a business goal is not given, state what you think the business goal should be.
- Describe your approach: Succinctly state how you will analyze the question.
- Personas: Identify personas. Describe their motivations and goals related to the product you are designing. What job do they want to get done using the product?
- Prioritize Personas: Choose personas that make the most business sense and explain why you chose them.
- Use Cases: Brainstorm different uses cases that will surface needs or pain points of the personas. There are various techniques to help spark ideas for good use cases. We describe some of these methods in “How would you design a bookshelf for children?”
- Solutions: Brainstorm solutions to support the use cases. Identify which use case each solution is solving.
- Prioritize Solutions: Evaluate solutions based on Impact vs. Effort or Impact vs. Cost. Under Impact, evaluate how much the solution will impact the user’s goals and the business goals. Under Effort, evaluate how complex the solution is. After selecting solutions that have the highest impact at the lowest effort, you may want to qualify the solutions based on risk level and how innovative they are. This will help break ties between solutions; or pick the solution that is most innovative and aligned with the business’s acceptable levels of risk.
- Metrics: State which metrics you would use to evaluate whether your product design is successful or not.
- Summarize: State what the design goal is, which personas you are targeting, what the personas’ main goals are, the solution you chose, and why it is the best solution.
Ask Clarifying Questions
INTERVIEWEE: Is this wedding registry for a big retail store like Macy’s, or a custom registry that the couple sets up to raise money?
INTERVIEWER: Assume it is a registry for a retail store.
INTERVIEWEE: Is the design for a web page or a mobile app?
INTERVIEWER: Let’s say it is a mobile app.
INTERVIEWEE: And, what is the business goal of designing a registry for the retail store?
INTERVIEWER: The goal is to increase revenue by selling more products.
Describe Your Approach
INTERVIEWEE: Ok, thanks. Here is how I would like to approach my analysis. I will start by understanding who the users of a wedding registry are, for a retail store like Macy’s. Next, I will surface what the users’ goals are concerning setting up a wedding registry, identify their needs for the wedding registry and list use cases. After that, I will propose some solutions to support the use cases, evaluate them and prioritize them. And, I will conclude with a recommendation. How does that sound?
INTERVIEWER: Sounds good, please continue.
INTERVIEWEE: Okay, regarding users, I see three different kinds of personas: the wedding couple, friends, and vendors.
Let’s start with wedding couples. There could be two types: younger couples and older couples. Younger couples, possibly in their twenties, are likely to live in an apartment or small space. And, they most likely will need basic furnishings to start their life together. So, their primary goal is to select basic furnishings. The people buying gifts for them are probably family friends, not personal friends. Therefore, a young couple would not be too concerned about the cost of the registry items.
Older couples, people marrying in their 30s or older, have likely acquired many home furnishings over the years. They either live together or have homes of their own, but will probably have duplicate furnishings, and will have to decide whether to keep, replace, or dispose of them. The people buying the gifts are most likely their personal friends. Therefore, they would be concern about how much their friends can afford. Older couples would not want their friends to feel bad if they could not afford to purchase a gift. So, they have two main goals: 1) to avoid receiving duplicate furnishings and 2) for everyone to feel good about what he or she can afford to pay.
The second persona is friends. Friends will vary in what they can afford. Most friends would want to buy the favorite gift of the couple. But, if friends cannot afford too much, they might be concerned about being perceived as stingy. Their main goal is to buy something the couple really appreciates even if they can only spend a little.
Lastly, are the vendors of home products. Their primary objective is to sell as many products as possible and probably obtain consumer data they can use to improve marketing.
Of these personas, I think the wedding couple is the most relevant because they select the products, which directly impacts the bottom line of the retail store. Would you agree?
INTERVIEWEE: Okay, since the wedding couple is the primary persona, we should prioritize them when thinking about the design of the registry. Do you agree?
INTERVIEWEE: Okay. Then, I would like to brainstorm about the wedding couples needs or pain points towards achieving their goals.
To recap, the younger couples’ goal is to select basic furnishings. And, for the older couple, it is to avoid receiving duplicate furnishings and for everyone to feel good about what he or she can afford to pay.
I will start with the younger couples’ needs and then the older couple. How does this sound?
INTERVIEWER: Good, go ahead, please.
Okay. While keeping the couples’ goals in mind, I will quickly brainstorm their needs when using a registry.
(The user draws a word association graph, connecting thoughts a persona may have when using a registry. The interviewee uses this process to brainstorm uses cases.)
Let’s start with use cases for young couples:
- A young couple would want to know which ‘basic’ furnishings are needed for a first home.
- If a young couple’s home is small, they would want to keep it uncluttered and to make sure the gifts fit.
- A young couple may need to put their gifts in storage, if they do not have a place to live yet.
- Young couples may not have the patience to choose gifts, if a wedding registry offers too many choices. They want the process to be simple and fast.
- Young couples would like to return or exchange unwanted gifts.
- Young couples may want to personalize their registry to make it fun.
Now, use cases for older couples:
- An older couple may have duplicate home items, so they probably don’t want triplicates, unless they need a new item to replace an old one.
- An older couple may want to add new items to the registry but are not sure what they need.
- Older couples may already have a full house and would only want necessary items.
- Older couples may need help with disposing of old items for new ones.
- Older couples do not want their friends feeling pressured into buying gifts they cannot afford. They want their friends to feel good about their purchase without “breaking the bank.”
- Similar to young couples, older couples would like to return or exchange unwanted gifts.
- And like young couples, older couples want the gift selection process to be fast and straightforward.
- Older couples may like to show their appreciation to friends on the registry page.
When purchasing gifts, speed and simplicity are common needs for both young and older couples. So the app design should strive to optimize these two traits.
Now, I would like to move on to ideating solutions that support these use cases.
INTERVIEWER: Please proceed.
INTERVIEWEE: The ability to return and exchange gifts is a must, it is part of most wedding registries, and won’t lead to a differentiated design. Therefore, I will not focus on returns and exchanges. Also, temporary storage as well as a disposing service, are nice to have features but not critical to the user’s goals. So, I will not prioritize these needs. Instead, I will focus on the rest of the needs which are more critical to the users.
Okay, I will start with solutions for young couples and then for older couples.
- (Young Couples) Basics package: A feature that displays the top ten choices of a ‘basics’ package that other couples with similar characteristics have chosen. These characteristics could be location, home size, and a word that describes the kind of decor the couple is attracted to such as modern, classic or retro. Then rank the results by popularity. This solution will take care of use cases: 1, getting the basics; 2, not cluttering their home; and 4, finishing the process fast.
- (Young Couples) Temporary storage: Have an option to rent temporary storage for gifts. This takes care of use case 3.
- (Young Couples) Personalized Welcome page: A customizable welcome page to show the couple’s personality and individuality to their friends. This takes care of use case 6.
- (Older Couples) Prevent duplicate home items: A feature that finds furnishings the bride and groom already have. Couples upload photos of items they own and the feature can suggest new replacements. This takes care of use case 1, prevent duplicate home items and provide suggestions on replacements.
- (Older Couples) New items: Similar to the previous solution, this feature lists products that neither groom nor bride currently own, but are very popular with other wedding couples. This takes care of use case 2.
- (Older Couples) Each-owns: A complementary solution to the previous two is to display items that the bride and groom currently own and ask if they want to replace them with a newer model. This solution helps couples become aware of each other’s belongings, so they do not add duplicates to the registry. And, couples can suggest replacements too. This takes care of their need to order only necessary items, which is use case 3.
- (Older Couples) Disposing service: A service feature to help couples dispose of items they are replacing. This takes care of use case 4.
- (Older Couples) Group-Buy: A feature where the couple can specify a maximum spending limit per person per gift. This feature allows multiple people to pitch in similar dollar amounts for a single gift. Friends with limited budgets can contribute to a high-value gift and feel good about it. This solution takes care of use case 5.
- (Older Couples) Personalized Welcome page: Similar to young couples, older couples may want to add a personal touch to their registry. This takes care of use case 7.
INTERVIEWER: How would you prioritize these solutions?
INTERVIEWEE: I would like to prioritize these solutions based on Impact vs. Effort. By impact I mean, impact on the user’s goals, business goal, simplicity, and speed of getting the job done. And by effort, how complex would it be to implement the solution. After a first prioritization pass, I will also consider innovation as an additional criterion to make a final pick of the best solution.
INTERVIEWER: Sounds good, please proceed.
INTERVIEWEE: Okay, thanks. I will start by using a table to make comparisons between these solutions.
(The interviewee begins by writing the solution names inside each cell in the Solution column.)
I think solutions 4, 5 and 6 can be grouped into one because they use the same principle of uploading photos and then suggesting gifts. I will group these solutions as the “Items to Add” solution. Now, the solutions boil down to four: Basics Package, Items to Add, Disposing Service and Group Buy.
Of these four solutions, the Basics Package has the highest impact. The Basics Package supports the primary goal of young couples, to receive recommendations for essential items and do it fast. And, it aligns with the business objective of maximizing sales. The Items to Add solution solves the problem of minimizing unneeded furnishings for the older couple. But this is not aligned with maximizing sales, so I think the Items to Add solution is less impactful.
The Disposing Service solution does not solve any of the main pain points of users, so it has the lowest impact.
The Group Buy solution is more relevant for older couples and meets their goal of preventing friends from feeling bad about what they cannot afford. However, this is not a significant feature for younger couples and can lead to fewer sales. Therefore, I think the Group Buy solution has a medium impact on overall goals.
From the four solutions, I pick the Basics Package and Items to Add solutions as the most impactful. And now, I would like to compare them relative to effort.
Regarding effort, the Basics Package solution would require developing a recommendation system based on machine learning algorithms that match packages to the couple’s location, home size, and style. The recommendation system should not be that hard to develop, and there should be plenty of historical data to train the algorithm. So concerning effort, I would say it is a medium effort.
The Items to Add solution would require more effort to build and more effort from the couple to upload photos. An image-recognition machine learning algorithm would need to be developed and tuned. So relative to the Basics Package, I think the effort would be higher.
The Basics Package and the Items to Add are both innovative solutions. In the short term, I would implement the Basics Package first because it has higher impact and demands lower effort. In the long term, I would include the Items to Add solution. This way, we target both types of couples and maximize revenue.
INTERVIEWER: How would you measure the success of the Basics Package solution?
INTERVIEWEE: The premise of the Basics Package solution is to solve a key need for young couples: to get basic home furnishings for their new home. And, if this solution is successful, it should also be a source of increased revenue.
So to measure success, I would use the following as key metrics:
If the Basics Package is successful, then we should expect young couples to choose one of these choices. So, I would measure the percentage of young couples that choose a Basics Package on a monthly basis, and if that percentage is growing.
The percentage of revenue that is from Basic package sales. If couples are indeed going with our recommendations, then this percentage should be high.
INTERVIEWER: Any ideas on how this solution would look as a mobile app?
INTERVIEWEE: Sure, could I have a few minutes to wireframe it?
(The interviewee takes a few minutes to sketch a wireframe of the solution as a mobile app.)
INTERVIEWEE: Okay, here is a design idea.
In this wireframe, there are two features: the Basics Package as the “From Scratch” option for young couples, and Items to Add as the “Midway” option for older couples. Since we are prioritizing the solution for the short term, I will only show the flow for young couples.
After sign up, the couple lands on the Registry screen. This screen shows two options: From Scratch and Midway. Young couples that need to furnish a new home would click on the “From Scratch” option that highlights an image of a young couple. Alternatively, if the user is an older couple, they would click on the “Midway” option that features an image of an older couple. Next, the young couple sees the “Packages” screen, where they are asked to enter their preferences for location, home size, and style.
As the younger couple enters different options for location, home size, and style, matches of packages are displayed and sorted by the number of “hearts,” which are likes from other couples. If the young couple likes one of the packages, they can select it and see details about the items. For example, if they click on the San Francisco Style package, then they are shown the furnishings from “San Francisco Style” screen. The style screen presents the young couple with a list of items to choose from. They can select items individually by putting a checkmark in the box on the right side of each cell.
Once the items are selected, another screen appears and shows a summary of selected items. I am not showing this screen since this is a typical checkout screen.
INTERVIEWER: Looks good. So can you summarize your analysis to wrap up?
INTERVIEWEE: Sure. The question was to design a wedding registry for a retail store. I defined three different types of users: couples, friends, and vendors. Based on the business goal of maximizing sales, I prioritized couples as the primary user to design for.
Within couples, there are two types: a younger couple and older couple. I determined that each couple has different goals when using a wedding registry. The young couple’s main goal is to select basic furnishings for their new home, while an older couple’s main goal is to avoid receiving duplicate furnishings and for everyone to feel good about what he or she can afford to pay.
Based on these goals, I listed needs for both couples and brainstormed solutions. The best two solutions were the “Basics Package” which would appeal to young couples and “Items to Add’ which would appeal to older couples. Since young couples are most likely to add more items to the registry than older couples, which is better for the business, I recommended implementing the “Basics Package” in the short term. And, the “Items to Add” feature in the longer term.
And, to evaluate whether the “Basics Package” solution is successful, I proposed two main metrics. The first one measures the percentage of young couples that chose a Basics Package. This metric will tell us if our suggestions are valuable to young couples. The second metric measures the percent of revenue that is due to the Basics Package solution. This metric will tell us how impactful this solution is to our bottom line.