Estimation question

Imagine you created a new type of product that would replace the mobile phone. How would you determine how many units to manufacture?

Practice this question out loud. An AI interviewer asks it, follows up like a real interviewer would, and scores your answer. Type or speak.

What this question tests

Tests structured demand estimation for a hypothetical new product category, forcing explicit assumptions about addressable market and adoption curve.

Clarify the scenario: a genuinely new device category replacing phones, assume something like AR glasses, launching to an initial target market.
Define the addressable market: start from global smartphone users, about 5 billion, as the theoretical ceiling, then narrow to a realistic early-adopter segment.
Estimate early-adopter penetration: assume 0.5% of smartphone users adopt in year one, about 25 million potential buyers.
Adjust for real launch constraints: limited initial country availability and price sensitivity, applying a further 20% reachable-market discount, about 5 million addressable buyers.
Estimate manufacturing units: plan initial production at 60-70% of the addressable estimate to avoid overproduction risk, roughly 3 million units.
State the key sensitivity: the estimate is highly sensitive to the adoption-rate assumption, so recommend a phased ramp tied to real pre-order data.

Builds top-down from a real anchor, global smartphone users, before narrowing with explicit adoption and reach assumptions.
Explicitly discounts for real launch constraints, geography and price sensitivity, rather than assuming instant global availability.
Recommends underproducing relative to the raw estimate and ramping with real demand signals, sound judgment for high-uncertainty launches.
Flags the adoption-rate assumption as the biggest source of estimate error, showing awareness of what could be wrong.

Guessing a units number with no anchor to a known market size or adoption logic.
Committing to a large upfront manufacturing number without acknowledging demand uncertainty for a brand-new category.

How would you adjust this if early pre-orders came in at half your estimate?
What would your minimum viable production commitment be to avoid a costly overrun?