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Machine Learning questions require understanding of core concepts and practice. PracHub provides solutions with explanations to help you master machine learning interviews.

What difficulty level is this interview question?

This is a medium difficulty Machine Learning question, commonly asked during Onsite rounds at DoorDash.

What role is this question designed for?

This question is commonly asked for Machine Learning Engineer candidates at DoorDash during technical interviews.

How would you target promotions to grow consumers?

Last updated: Mar 29, 2026

Quick Overview

This question evaluates the ability to design and operationalize ML-driven promotion targeting and measurement systems, assessing competencies in causal inference and uplift estimation, experimentation design, metric selection, budget-aware optimization, and monitoring for long-term impact.

DoorDash

Oct 17, 2025, 12:00 AM

Machine Learning Engineer

Onsite

Machine Learning

ML / Growth Scenario

You own a system that sends promotion offers (e.g., "$10 off", "free delivery") to consumers to increase growth.

Prompt

Design an approach to decide:

Who should receive a promo
What promo to send (offer type/amount)
When to send it

Constraints and concerns:

Limited promo budget
Risk of giving discounts to users who would have ordered anyway
Need to measure incremental lift (not just conversion)
Avoid harming long-term margin or creating promo addiction

Explain your modeling/experimentation strategy, data needs, evaluation metrics, and how you would deploy and monitor it.

Solution

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