Launch Decision for a More Accurate Model That Is Twice as Slow
Company: Google
Role: Product Manager
Category: Product / Decision Making
Difficulty: medium
Interview Round: Other
You are the product manager for a feature powered by a machine-learning model. The team brings you a candidate model that is 20% more accurate than the model now in production, but its latency is twice as high. Would you ship it? Walk the interviewer through how you reach the decision.
```hint Price both numbers for the user
Convert the accuracy gain and the extra wait into what a user of this feature actually experiences, and ask whether the decision really has to apply to every request in the same way.
```
### Clarifying Questions
- Which product and surface does the model power: an interactive experience such as search, autocomplete or chat where people wait for the result, or a background task such as classification, ranking or batch summaries?
- Is the 20% a relative gain or 20 percentage points, on which metric (error rate, precision on a key class, human-rated quality), and was it measured offline or with real users?
- What are the current latency figures in absolute terms, and is "twice as high" measured at the median, at the slow tail, or as time to the first visible output?
- Does the slower model also cost more to serve, and does this surface have a fixed latency budget or service commitment?
### What a Strong Answer Covers
- Translating both numbers into impact on this surface: the baseline behind the 20%, where the gain lands, and whether the absolute added delay is noticeable
- Validating the offline gain with an online experiment that measures the accuracy and latency effects directly
- Options between shipping and holding, such as routing requests, reducing latency, changing the interface or a targeted rollout
- Guardrails and costs: serving cost and capacity, slow-tail latency and timeouts, abandonment, and segments such as users on slow networks
- A committed recommendation with the results that would change it
### Follow-up Questions
- The online test shows higher task success but a small, steady decline in sessions per user over a month. What do you recommend?
- Engineering says it can cut the new model's latency substantially within two quarters. Do you wait, ship now, or ship to part of the traffic?
- How would your reasoning change if the model supported a medical or financial decision instead of a consumer feature?
Overview: A product manager decision question about whether to launch a machine-learning model that is 20% more accurate than the current one but twice as slow. It tests how a candidate turns an accuracy and latency trade-off into user and business impact, validates it with an online experiment, and weighs options between shipping and holding.