Dataford
Top 29
Prep plan
Updated weekly · Last refresh Aug 30

Persistent Data Scientist Interview Questions

The questions to prepare for a Persistent Data Scientist interview. Questions from real interview reports rank first. Updated weekly.

29questions
~4htotal time
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1
SQL & Data ManipulationStart here. 5 questions + 2 drills · ~62 min
Running Average With Window FunctionsEasy
Practice

Calculate each Hinge user's 30-day rolling average of daily interactions using CTEs and window functions.

Window FunctionsData AnalysissqlPersistent
Handling Missing and Skewed DataMedium

Explain how to handle NULLs, skewed values, and outliers when preparing an analysis dataset using SQL.

Data Qualitynull handlingData WranglingPersistent
Second Highest Trader SalaryEasy
Practice
Recently asked
Practice drill

Find the second highest distinct salary from a single table using basic PostgreSQL ordering and limiting.

SubqueriesRankingSortingeClinicalWorksInformaticaSpectraforce Technologies
Second-Highest Salary Without LIMITEasy
Practice
Practice drill

Use nested aggregation subqueries to find the second-highest distinct salary without LIMIT.

Subqueriessql queryPersistentPersistent Systems
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2
Metrics3 questions · ~25 min
First Checks for Metric DropsEasy

Outline the first checks to diagnose a sudden drop in a core product metric, starting with data quality, scope, and decomposition.

Lagging IndicatorsLeading IndicatorsDiagnosisPersistent
Analyze New Feature EngagementMedium

Assess a new feature using adoption, activation, repeat usage, and retention metrics tied to user value.

Leading IndicatorsA/B TestingEngagement MetricsPersistent
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3
A/B Testing & Experimentation6 questions · ~50 min
Common Pitfalls in Experiment ResultsHard

Identify the main pitfalls that can distort A/B test interpretation and explain how to guard against them.

PeekingNovelty EffectSample Ratio MismatchPersistent
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4
Product Sense3 questions · ~25 min
Designing Engagement Product MetricsMedium

Assesses how you translate product goals into measurable, reliable metrics.

product metricsdesignuser engagementPersistent
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5
Machine Learning4 questions · ~34 min
Advanced ML and GenAI TopicsHard

Evaluates depth across ML, DL, and GenAI design choices relevant to production systems.

GenAIDeep LearningPersistent
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6
Behavioral & Leadership7 questions · ~59 min
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7
More topics1 question · ~8 min
Statistical Significance in A/B TestsMedium

Evaluates your understanding of hypothesis testing and decision-making in experiments.

Statistical SignificancePersistent
The finish line: interview-readyComplete all 29 questions plus 2 hands-on drills to finish this plan.