Most people think product sense is a finnicky exercise in creative genius. It's not. Once you learn the formula, you'll reliably nail the interview — every time.
This interview is less about your ability to come up with brilliant product ideas on the spot — and much more about your ability to methoditically explore the search space, communicate clearly and make strong, framework-driven decisions.
Start the interview by listening carefully to the question, asking any clarifying questions and laying out the structure you'll follow. The structure we recommend:
It's less important what exact structure you pick, but it's critical you use something and lean on it as the backbone for your thoughts.
Align with the interviewer on the goal: what are we optimizing for? This will come in handy later in the interview.
The interview is less about "being right" and much more about your ability to clearly articulate your decisions, always be crisp about decisions you make.
Identify the core users of the product.
For each user, identity their needs. Focus on being creative and thorough: doing this well is critical to being able to generate thoughtful solutions.
This section can easily be the biggest part of the interview, frequently close to half of the 30-35 minute interview.
It's absolutely essential that you only advance to the solution stage once you feel you've really explored needs and have the right background to be able to generate big, impactful solutions.
Brainstorm solutions that solve the user needs. Focus on generating big ideas that genuinely have a shot at meaningfully moving your goal. This will come naturally if you explored user needs well.
In this step, you collect all the information you brainstormed in the solution phase and make a clear, structured proposal.
You'll likely be pressed for time at this point, but make sure to always continue to make clear, articulate arguments. The interviewer will likely give you a few minutes for your questions at the end.
The #1 reason for rejection is, in some way or another, tied to communication. Being a PM at a place like Facebook requires a very high standard of communication and decision-making clarity.
If you master these simple tips, your performance will improve leaps & bounds. Practice mock interviews with others and be ruthless in your standards for communication.
If you find yourself coming up with small, incremental solutions, it's because you're making too many hard decision early on (e.g. picking one user segment or picking one user need). Realistically, Facebook isn't interested in a product that helps e.g. seniors or college students with one minor use case.
To develop big ideas, give yourself space to focus on solutions that help a big group of people and solve many user needs.
Postpone picking until the solution stage, and leave as much of the search space open as possible.
For example, you can describe user segments, but don't pick one user segment unless absolutely necessary and you're getting something very meaningful in exchange for cutting the impact/opportunity of the product.
Instead of thinking about "Joe" and "Mary" and their different painpoints with the product, focus on core needs that are true of all personas. This will help you a lot come up with genuinely impactful products.
Focus on aspirational needs over functional needs. For example, instead of thinking "what's wrong with Groups today", think more "Why do people use Groups? What do they fundamental want?".
If you identified needs like "feel connected", "feel in the know", "be part of an in-group", etc., perhaps you would have suggested VR-based solutions or radical new ways of hanging out virtually.
Thinking of core needs (rather than painpoints) will help you identity solutions that go beyond shuffling some pixels around in the existing product.