Reddit Data Scientist Interview Questions
Reddit Data Scientist interview questions typically blend product-minded analytics, experimentation, and hands-on coding. Expect the process to evaluate analytical depth, statistical rigor, and how you translate signals from diverse communities into product decisions. Distinctive features include emphasis on A/B test design and interpretation, clear communication of tradeoffs to cross-functional partners, and practical data-wrangling with SQL and Python. Interviews often mix a recruiter screen, a technical screen (SQL/Python and statistics), a case-style product or experimentation interview, and a final loop that assesses business impact and collaboration. For interview preparation focus on three threads: sharpen SQL and pandas fluency for messy joins and aggregations, refresh statistics and experiment design intuition including power and false positives, and practice framing product analytics problems end-to-end with concise storytelling. Work through a few timed case studies, rehearse clear STAR-style examples of projects and tradeoffs, and be ready to ask clarifying product questions. This combination of technical polish, product sense, and communication is what most teams at Reddit typically evaluate.

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Design A/B test for AI chat box
Context A social platform (e.g., Reddit) plans to launch an AI chat box that answers user questions. The functionality overlaps with the existing Sear...
Measure impact of ads-manager automation feature
Context An Ads Manager product has new automation features (e.g., auto-bidding, auto-budgeting, auto-creative suggestions). You need to measure the fe...
Collaborate with PM and Eng as DS
Question As a Data Scientist working with Product Managers and Engineers: 1. How do you structure collaboration (requirements, timelines, ownership)? ...
Query US-based users and most active forums
You are given user and post data for an online forum platform. Tables (schemas) Assume the following tables: users - user_id BIGINT (PK) - home_countr...
Justify synthetic control and handle inference
Synthetic Control: Assumptions, Estimation, Inference, and Diagnostics Context You are estimating the causal effect of an intervention on a single tre...
Design a causal evaluation without A/B testing
Non-Randomized Launch Decision via Synthetic Control: Complete Analysis Plan You need to make a go/no-go decision for a high-impact feature that canno...
Prioritize competing engineering requests
Scenario You are a Data Scientist/Analytics partner supporting multiple engineering teams. Two (or more) teams simultaneously ask you to prioritize th...
Design experiment for ads in chat with budgets
Context After launching an AI chat feature, the company wants to show ads inside the chat experience (you are interviewing for an Ads/Monetization dat...
Communicate and de-risk a non-experimental launch
Decision-to-Launch Plan After a Synthetic Control Result Context You are a data scientist who used a Synthetic Control method to estimate the causal i...
Compute P(A>B) for m- and n-sided dice
Two fair dice are rolled independently: - Die A has m faces labeled \(1,2,\dots,m\). - Die B has n faces labeled \(1,2,\dots,n\). Each face is equally...