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Coinbase·Data Scientist·Technical Phone Screen·Intermediate

Intermediate
May 2026

Summary

Coinbase DS interview with a product estimation problem centered on a real-world scenario. Pretty open-ended, which I wasn't fully ready for. The QR code angle made it feel more grounded than a typical 'estimate X users' question.

Questions Asked (1)

Q1

A Coinbase Super Bowl ad shows a QR code linking to a promo. Estimate how many viewers actually scan and use it. Walk through your assumptions, any data sources you'd reference, and the full calculation.

Product Analytics & MetricsProduct Sense & Ideation
Author's notes

I started with Super Bowl viewership (around 100M) and worked down through layers: who has a phone out, who's actually paying attention during the ad, who bothers to scan, and who completes the promo.

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AI HintsAI Generated

Suggested Approach

Break the problem into a funnel: total Super Bowl viewers → those who noticed the ad → those who scanned the QR code → those who signed up → those who used the promo. Use publicly available data (e.g., Nielsen ratings, social media buzz) and reasonable assumptions to estimate each stage, then multiply through to get a final number.

Pro tip: Anchor your estimate with a known benchmark (e.g., typical QR code scan rates for TV ads are 0.1-1%) and then adjust for Coinbase's unique context (e.g., tech-savvy audience, controversial ad). This shows you can combine external data with product-specific insights.

1. Estimate total Super Bowl viewership

Use Nielsen data or public reports to estimate the average live audience (e.g., ~100 million viewers in the US). Consider that not all viewers watch the ads (e.g., some skip or are not paying attention).

2. Estimate ad recall and QR code notice rate

Assume a certain percentage of viewers actually saw and remembered the ad. For a high-profile Super Bowl ad, recall can be 30-50%. Then, estimate what fraction noticed the QR code (e.g., 50% of those who saw the ad).

3. Estimate scan rate among those who noticed

Use industry benchmarks for QR code scans from TV ads (often 0.1-1% of viewers). Adjust based on factors like ad creativity, call-to-action strength, and audience demographics (Coinbase's target audience may be more likely to scan).

4. Estimate conversion from scan to sign-up and promo usage

Not everyone who scans will complete the sign-up and use the promo. Assume a conversion rate (e.g., 20-50% for sign-up, then 50-80% for promo usage). Multiply through to get final number.

5. Sanity-check and present final estimate

Compare your final number to any publicly reported results (e.g., Coinbase reported 20 million hits in one minute, but that's website visits, not unique users). Adjust assumptions if needed and present a range.

Key Points to Mention

  • Use of external data sources: Nielsen ratings, industry benchmarks for QR code scans, Coinbase's public statements.
  • Funnel approach: breaking down the problem into sequential stages with conversion rates.
  • Assumptions should be clearly stated and justified (e.g., ad recall rate, scan rate).
  • Consideration of unique factors: Super Bowl audience size, Coinbase's brand and target demographic, ad controversy driving curiosity.
  • Differentiate between scans, sign-ups, and promo usage; not all scans lead to conversions.
  • Sanity-check with known outcomes (e.g., Coinbase reported 20M hits in a minute, but that's not unique users).

AI-generated suggestions, not part of the candidate's original notes. May be inaccurate — verify before relying on them.