Using the Super-Specific Who in Case Interviews
TL;DR - Read Lenny Rachitshy’s piece on the Super-Specific Who to understand why I keep telling you to get more specific with your user segmentation. You are mimicking and referencing the search for product-market fit in your case interview.
For years, I have been coaching candidates to get more specific with their user groupings as it leads to better results. Most still live in fear of what Lenny Rachitshy calls the super-specific who for their case interview answers.
Don’t Get Caught in Common Traps
Many candidates get hung up on being MECE (mutually exclusive, collectively exhaustive) as if checking off a requirement, rather than realizing that instruction is directionally correct, not a hard and fast rule. Or, they fear they are getting too specific and thus will fail. Or they heard somewhere on a YouTube video that they needed to focus on the largest total addressable market and so skip to prioritizing for that market.
These candidates forget that the case interview is intended as an exercise that somewhat reflects reality. If you look at what successful startups do, time and again, it is about finding a super-specific user for whom they can solve a problem and find product-market fit.
Yes, they these startups believe that eventually the mass-market will adopt their product, but to test it out and to think about where they should focus first, most successful startups start with specific users. (You can even remind your interviewer of that when prioritizing.)
Examples of companies that started with Super-Specific Who:
Yelp - 25-35-year-old women in cities
Discord - Gamers of PCs playing Final Fantasy XIV
Tinder - Attractive, party-loving college students in LA
Netflix - Online DVD fanatics
TikTok - Young lower-tier influencers on Facebook or Instagram
Cameo - B-List athletes in Chicago
Instagram - Designers interested in photography with a large Twitter following
Airbnb - Conference-goers traveling to a city where hotels were booked up
DoorDash - Independent restaurant owners in suburban markets
Substack - Successful veteran online newsletter writers
Lyft - Young tech employees in San Francisco
LinkedIn - Successful professionals in Silicon Valley
Robinhood - Millennials who don’t have a lot to invest
What’s App - Russian emigrants in San Jose
Product-Market Fit
If you read articles or books that address product-market fit, you will see they talk about finding the following measures for their core (user-specific) users before they try to go to the mass market (early/late majority).
Product market-fit can be measured by:
High cohort retention
High growth rate
10x better than the leading alternatives
Willingness to pay
The 40% Rule (not my favorite)
High Customer Lifetime Value
In Conclusion
When trying to come up with three user segments to consider during your next product case interview, think about all those companies that succeeded by starting with the super-specific who.
References:
Lenny Rachitshy’s piece on the Super Specific Who
Crossing the Chasm by Geoff Moore
