Most candidates lose the case study in the first five minutes
Eighty minutes of video on the case study round, taught the way I teach it in a mock interview. $199, and the first part is free to watch below.
I have run mock interviews with candidates going for senior and staff roles at Airbnb, Uber, Amazon, Meta, Google, and a dozen other companies, and the same thing happens in most of them. The candidate hears the prompt and goes straight to experimental design. No discussion of what the change actually does to users, no walk through the ecosystem it sits inside, and no argument for the metric before the test gets built around it.
That is not a knowledge problem, because these are people who can design an experiment properly and often do it for a living. It is a structure problem, and an expensive one, because an interviewer forms a view of your product judgment in the first few minutes and you rarely get to reset it.
Then, once the answer is inside experimental design, it usually stays there. The parts that separate a strong answer from a competent one never come back:
- Winners and losers from the change, and who is quietly made worse off
- Unintended consequences that show up somewhere other than the metric being moved
- The guardrail metrics that have to hold for the result to mean anything
- Short-term lift against long-term effect, and which one the business is actually buying
Case studies have broadened since 2024, and the Playbook covers the newer formats, but this one is still the most common thing you will meet. It is the launch evaluation: we want to ship this, how do we know whether it is a good idea.
It replaces the session most people book first
Most people who come to me want a mock case study, and with anyone I have not worked with before, the first session is almost always the same conversation. We spend it rebuilding how the answer is structured rather than working on anything specific to them.
A 45-minute session costs $275, and a large share of that time goes on material that does not change from one candidate to the next. So I recorded it, and what came out runs eighty minutes, nearly twice the length of a session, at $199 and rewatchable as often as you need.
If you then book a session, we start from a much better place and spend it on you rather than on the framework.
Six parts, eighty minutes
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Introduction: the framework that changed my interview results
7:57Where the framework came from and what it fixes. This part is free to watch below.
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The three-part framework, in overview
4:12The shape of a complete answer, so you can see where each piece belongs before going deep on any of them.
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Part one: product sense
10:29Reading the treatment and the ecosystem before you touch measurement. Who the users are, what the change actually does to them, and what a marketplace does in response.
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Part two: metrics
16:54Choosing a primary metric and defending it, the guardrails that have to sit alongside it, and the metrics that look obvious and quietly mislead.
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Part three: measurement
26:38Experimental design once the thinking above is done, including what to do when user-level randomization is not available to you.
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A complete case study, worked start to finish
18:24The whole framework applied to one problem in real time, at the pace an interview actually moves.
Video rather than written, deliberately, because the framework is easier to follow when you can hear where the emphasis goes and watch an answer get built in order.
Watch the first part before you decide
The opening part is open to everyone with no email required, and it is the same material paying readers get.
Recorded before the 2026 interview season, so the offers it names are the earlier ones. This is the framework I then took into 80+ rounds that Spring and converted five of eight final rounds with.
This, or the Playbook
Buy this on its own if the case study is the round you are losing, you have not passed a competitive one yet, and you want the structure fixed before your next loop.
Buy the Playbook instead if you want the whole interview loop. All eighty minutes of this series sit inside it as a standalone chapter at no extra cost, so buying the Playbook gets you both. There is no coupon to claim and no second enrollment.
Do not buy both. If you buy this first and want to move up later, get in touch and I will sort it out.
Get the structure right first
Eighty minutes on the round most candidates are losing, from someone who ran 80+ interview rounds this Spring and coaches people into senior and staff offers at the companies you are targeting.
Master the Case Study
The launch evaluation archetype, taught end to end: product sense, metrics and guardrails, measurement, then a complete worked case.
$199 Get the series →The Data Science Interview Playbook
Every round in the loop, with this series included as a standalone chapter. The right choice if the case study is not your only gap.
$499 See what it covers →