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Harnham Interview Questions

data and analytics recruitment is our core business and we’re proud to say, our customers believe we’re good at it. in our most recent customer satisfaction survey, 95% of respondents said that they would recommend harnham. harnham has actively chosen to focus on data and analytics, we’ve immersed ourselves in this market and are now an integral part of this business community. our capability has grown to provide recruitment services and advice across the marketing analytics, credit risk, data science, data and technology and digital sectors.

data and analytics recruitment is our core business and we’re proud to say, our customers believe we’re good at it. in our most recent customer satisfaction survey, 95% of respondents said that they would recommend harnham. harnham has actively chosen to focus on data and analytics, we’ve immersed ourselves in this market and are now an integral part of this business community. our capability has grown to provide recruitment services and advice across the marketing analytics, credit risk, data science, data and technology and digital sectors.

Overview

A/B Testing

Algorithms

Analytics

Machine Learning

Probability

Product Metrics

Python

Statistics

Harnham Interview Guides

Suppose there exists a new airline named Jetco that flies domestically across North America. Jetco recently had a study commissioned that tested the boarding time of every airline, and it came out that Jetco had the fastest average boarding times of any airline.

What factors could have biased this result, and what would you look into?

What could potentially bias the average boarding time in favor of an airline that only flies domestically?

What could potentially bias the average boarding time in favor of an airline that only flies domestically?

Boarding Times Bias

A new airline came out as the fastest average boarding times compared to other airlines.  What factors could have biased this result and what would you look into?

You are testing hundreds of hypotheses with many t-tests. What considerations should be made?

What is a key disadvantage of the F-test when compared to multiple t-tests?

What is a key disadvantage of the F-test when compared to multiple t-tests?

Hundreds of Hypotheses

You are testing hundreds of hypotheses with many t-tests. What considerations should be made?

In an A/B test, how can you check if assignment to the various buckets was truly random?

In an A/B test, which of the following is a common method to determine if the assignment to the test groups was truly random?

In an A/B test, which of the following is a common method to determine if the assignment to the test groups was truly random?

Random Bucketing

A/B Testing & Experimentation

Product Manager | AI SaaS | Up to £105,000 + Equity We’re working with a fast-growing AI SaaS company that is transforming how property management firms run their operations. Their intelligent automation platform streamlines compliance, maintenance, lettings and tenant support — reducing admin workload by up to 80% through AI-driven workflows and natural language assistance. They are now looking for a technically minded Product Manager to lead the evolution of their core product and shape the roadmap as they scale. The OpportunityYou’ll own the full product lifecycle from discovery through MVP and commercial rollout, working closely with founders and engineers to define vision, drive execution, and deliver meaningful automation at scale. This is a hands-on role for a PM who thrives on solving complex problems and collaborating deeply with technical teams. Key Responsibilities<ul><li>Define and communicate product strategy, goals, and success metrics</li><li>Lead discovery, validation, launch, and iteration of new AI-driven features</li><li>Work with cross-functional teams to prioritise and deliver results quickly</li><li>Translate user insights into data-backed roadmaps and measurable outcomes</li><li>Collaborate with GTM teams on positioning, pricing, and launch strategy</li><li>Report directly to the founding team on progress, risks, and next steps</li></ul> Skills & Experience<ul><li>3+ years of Product Management experience in B2B SaaS or platform products</li><li>Strong technical literacy, ideally from a software or development background, or with hands-on experience building or prototyping in Python</li><li>Proven success taking early-stage products (0→1) to market and scaling them</li><li>Comfortable discussing APIs, architecture, and data pipelines</li><li>Strong analytical mindset; confident using data to guide decisions</li><li>Excellent UX instinct with a focus on simplifying complex workflows</li><li>Familiarity with Figma, A/B testing tools (such as Replit), and rapid prototyping platforms (v0.dev, Lovable)</li></ul> What’s on Offer<ul><li>Up to £105,000 base salary</li><li>Strong Equity options</li><li>High-impact role with ownership over product, culture, and strategy from the ground up</li><li>This role can't sponsor</li></ul> Apply below!

SENIOR PRODUCT ANALYTICS MANAGERHYBRID - LONDON - 2 days a week in the officeSALARY - UP TO £100,000 ABOUT THE COMPANYA fast-growing membership platform offering exclusive offers and rewards. With a huge membership base and growing business, they are now looking to expand their data team! THE ROLEAs a Senior Analytics Manager you will:<ul><li>Lead a team of 3 Senior Analysts</li><li>Use insight to understand user behaviour, friction and value drivers</li><li>Partner closely with product teams to solve problems and shape strategy</li><li>Define core product metrics and ensure accuracy and adoption across teams</li><li>Lead experimentation design and uplift analysis to drive continuous improvement</li><li>Build dashboards and self-serve tools for faster decision-making</li><li>Deliver clear, commercially aligned recommendations to senior stakeholders</li><li>Maintain a structured knowledge base of product insights and learnings</li><li>Deliver experimentation roadmaps and hypothesis-driven product improvements</li></ul> YOUR SKILLS & EXPERIENCE<ul><li>Prior experience as a manager</li><li>Strong SQL with hands-on experience analysing product data</li><li>Exposure to dbt and version-controlled analytics workflows</li><li>Python for deeper analysis and exploration</li><li>Experience with modern BI tools (Lightdash / Looker or similar)</li><li>Strong communication and data storytelling</li><li>Background in product analytics in consumer-facing digital businesses</li></ul> BENEFITS & SELLING POINTS<ul><li>Salary up to £100,000</li><li>Hybrid Working</li><li>Great opportunity to join a growing team and business</li></ul>

Head of Data Management£85,000 to £100,000 + PackageHybrid – Nottingham (3 days a week) Are you an experienced data leader looking to define and shape how an organisation manages and governs data? This is a newly created role within a major enterprise going through a large-scale transformation, offering the autonomy to redesign data practices from the ground up. Sitting one level below Director, you will lead a team of 12 (including four Managers) and take full ownership of data management strategy, data governance, and the end-to-end data lifecycle. This is a fast-paced, high-impact environment where you’ll influence senior stakeholders, work closely with Risk, Technology and the Chief Data Office, and drive enterprise-wide improvements across data quality, privacy, and governance. The RoleIn this strategic yet hands-on position, you will<ul><li>Own the organisation’s Data Management Strategy and drive business-wide change</li><li>Lead data stewardship across analytical, operational and policy domains</li><li>Shape and improve data governance, quality frameworks, and risk policies</li><li>Oversee the full data lifecycle, ensuring data is discoverable, high quality, and well governed</li><li>Partner with senior leaders, Risk, the DPO and Technology to meet regulatory and privacy requirements</li><li>Guide the organisation through a major data management transformation</li></ul> Technical Focus<ul><li>Strong understanding of ETL, APIs and modern cloud data ecosystems</li><li>SQL and Python expertise (automation experience strongly valued)</li><li>Knowledge of data quality tooling (e.g. Informatica)</li><li>Understanding of data architecture, governance frameworks and lifecycle management</li><li>Experience working within regulatory or data-risk environments is highly advantageous</li></ul> What They’re Looking For<ul><li>An established people leader comfortable managing high-performing teams</li><li>Experience delivering data management transformations</li><li>Strong regulatory understanding (GDPR experience beneficial)</li><li>Ability to influence senior stakeholders and communicate complex data topics with clarity</li><li>Backgrounds may include: Data Management, Data Quality, Governance, Architecture or senior technical roles that have pivoted into leadership</li></ul> Why Apply?This is a rare opportunity to step into a high-impact leadership role with the freedom to redefine how data is governed within a major organisation. You’ll shape the roadmap, influence enterprise standards and set the vision for how data is managed in the future.

⭐ Product Data Scientist - Up to £65k + Benefits | London (Hybrid) Join a fast-growing, community-driven marketplace on a mission to make fashion circular. We're looking for a Product Data Scientist who can turn complex data into actionable product insights, drive experimentation, and influence strategy across a major consumer platform.What you'll do<ul><li>Own analytics for a core product area</li><li>Shape product & commercial strategy with data-led insights</li><li>Design, run, and evaluate A/B tests end-to-end (3-5 per quarter)</li><li>Partner with Product, Engineering & ML teams</li><li>Help build self-serve analytical capabilities</li></ul>What you'll bring<ul><li>Strong SQL (day-to-day level)</li><li>Python exposure (nice to have)</li><li>Experience with BI tools (Looker/PowerBI/Tableau)</li><li>Comfort working with ETL workflows</li><li>Strong communicator with commercial awareness</li><li>Confident presenting to non-technical stakeholders</li></ul>Why apply?<ul><li>Up to £65k base</li><li>1 day a week in a central London office</li><li>Exceptional benefits</li></ul>If you're driven by experimentation, impact and product thinking, this is a brilliant next step.Find out more and apply via the link below.

Customer Analytics ManagerLocation: LeedsSalary: £60,000–£70,000 + 10% bonus I’m partnering with a market-leading, high-growth consumer healthcare brand that’s scaling fast and doubling down on customer insight as a strategic growth engine. They’re investing heavily in data, tech, and analytics maturity -Mand they’re looking for a commercially switched-on Lead Insight Analyst to take full ownership of their customer strategy. The RoleYou’ll be the go-to for all things customer insight: shaping strategy, driving adoption of actionable analytics, and leading a team of four analysts. Expect to get stuck into LTV modelling, segmentation, RFM frameworks, campaign optimisation, and partnering closely with Data Science to embed predictive insight across the customer lifecycle. What You’ll Bring<ul><li>Excellent SQL and hands-on analytics capability</li><li>Experience applying predictive models (no need to build from scratch)</li><li>Broad research/insight toolkit</li><li>Strong communication and stakeholder influence - you’ll need presence</li><li>Ability to translate complex customer behaviour into clear, commercial action</li></ul> Apply via the link!

Senior Machine Learning Engineer – Conversational AI???? Location: Chicago, IL (Hybrid – 3 days onsite)???? Salary: $180–200K base + 15% bonus + equity About the OpportunityHarnham is partnering with a fast-growing AI technology company that is building a next-generation agentic voice platform for enterprise-scale customer engagement. This organization works with Fortune 50 businesses across healthcare, finance, and retail, and is backed by leading investors with over $25M in funding. They are scaling rapidly and seeking an experienced Senior Machine Learning Engineer to join a high-performing team and help shape the future of conversational AI. The RoleYou’ll be responsible for fine-tuning and deploying advanced models for real-time voice applications, working on cutting-edge challenges in LLMs, speech technologies, and MLOps. Key Responsibilities<ul><li>Fine-tune and optimize large language models using LoRA, QLoRA, RLHF, and other advanced techniques</li><li>Deploy models into production environments with sub-second latency</li><li>Collaborate with engineering and product teams to deliver scalable solutions</li><li>Innovate with the latest research in conversational AI and speech technologies</li></ul> What We’re Looking For<ul><li>5+ years of ML engineering experience (beyond academic projects)</li><li>Strong background in model fine-tuning and deployment</li><li>Experience with GPT-class models, LangChain/LangGraph, and prompt engineering</li><li>Bonus: Speech expertise (ASR/TTS) and MLOps experience</li></ul> Why Apply?<ul><li>Competitive compensation + bonus + equity</li><li>Work on industry-disrupting AI solutions</li><li>Collaborative culture with real impact</li><li>Relocation support and hybrid flexibility</li></ul>

Senior Software Engineer – Build Next-Gen Conversational Platforms???? Location: Chicago, IL (Hybrid – 3 days onsite) ???? Salary: $230K base + 15% bonus + equity About the OpportunityHarnham is working with a fast-growing AI technology company that is building a next-generation agentic voice platform for enterprise-scale customer engagement. This organization partners with Fortune 50 businesses across healthcare, finance, and retail and is backed by leading investors with over $25M in funding. They are scaling rapidly and seeking an experienced Senior Software Engineer to join their engineering team and help shape the future of conversational AI. The RoleYou’ll design and build core platform components, working on backend services and APIs that power real-time voice applications. This role requires strong CS fundamentals, experience in scalable architectures, and collaboration with ML engineers and product teams. Key Responsibilities<ul><li>Develop backend services and APIs for high-concurrency, real-time applications</li><li>Design scalable, secure architecture for cloud-based systems</li><li>Work across backend and some frontend layers (full-stack experience is a plus)</li><li>Implement solutions in AWS ecosystems (EKS, Lambda, S3)</li><li>Optimize data models and pipelines using Postgres</li><li>Collaborate with ML engineers and DevOps to integrate AI models into production</li><li>Mentor junior engineers and establish best practices in coding, testing, and CI/CD</li></ul> What We’re Looking For<ul><li>6–7+ years of software engineering experience</li><li>Strong CS fundamentals (data structures, algorithms, architecture)</li><li>Experience with AWS services and containerized environments (Docker/Kubernetes)</li><li>Proficiency in backend development (Java, Python, or similar)</li><li>Exposure to frontend frameworks is a plus</li><li>Familiarity with distributed systems and high-performance architectures</li></ul> Why Apply?<ul><li>Competitive compensation + bonus + equity</li><li>Work on industry-disrupting AI solutions</li><li>Collaborative culture with real impact</li><li>Relocation support and hybrid flexibility</li></ul>

Senior Data Analyst - Marketing Analytics Location: NYC - Hybrid | Salary: $120,000 - $145,000 We're partnered with an innovative technology company that's redefining how people engage with live and digital experiences. With a strong commitment to data-driven decision-making, their Marketing Analytics function plays a central role in shaping growth strategy, optimising performance across channels, and deepening understanding of the customer journey. They're now seeking a Senior Data Analyst to join this high-impact team - someone who can bridge the gap between marketing strategy, business objectives, and analytical insight to drive measurable results. The Role <ul><li>Partner closely with Growth, Marketing, and Product teams to identify opportunities, measure campaign performance, and guide strategic decision-making.</li><li>Own analytical projects end-to-end, from scoping business questions to delivering actionable insights and recommendations.</li><li>Analyse and optimise customer acquisition, engagement, and retention across multiple marketing channels.</li><li>Develop and maintain core marketing datasets and dashboards using tools such as Looker, dbt, and Hex.</li><li>Evaluate campaign and channel effectiveness through experimentation and advanced statistical techniques.</li><li>Communicate complex analytical findings clearly and persuasively to both technical and non-technical stakeholders.</li><li>Act as a thought partner, using analytics to influence broader marketing and growth strategy.</li></ul> What You'll Bring <ul><li>4+ years' experience in Marketing Analytics, Growth Analytics, or a related data-driven role (ideally within tech, ecommerce, or consumer products).</li><li>Strong SQL skills and proficiency in Python or R for data manipulation and modelling.</li><li>Proven experience analysing marketing funnel performance, attribution, and ROI.</li><li>Hands-on experience with experimentation, A/B testing, or incrementality analysis.</li><li>Strong understanding of digital marketing channels, CRM, and performance metrics.</li><li>Excellent storytelling and presentation skills - able to translate data into strategic insight.</li><li>A proactive, collaborative mindset and a passion for driving business impact through analytics.</li></ul> Desirable: experience in B2B2C environments, working with marketing automation or attribution platforms, and exposure to data infrastructure (dbt, event tracking, marketing APIs). Tech Stack Airflow | Fivetran | Python | dbt | Redshift | mParticle | Eppo | Mixpanel | Looker | Hex | GitLab If you're passionate about using data to drive marketing performance and influence strategic growth decisions, this is an opportunity to make a tangible impact within a forward-thinking organisation.Get in touch with the Harnham team today to learn more.#MarketingAnalytics #DataAnalytics #GrowthAnalytics #Harnham #DataJobs #AnalyticsCareers

Senior Product AnalystOnline Sustainable MarketplaceUp to 80k A high-growth, community-driven marketplace is looking for Product Data Scientists to join a central insights function. The team partners closely with Product, Engineering and ML to shape product strategy, deliver experimentation, and guide commercial outcomes. This is an opportunity to take ownership of a core product area, drive data-led thinking, and influence the wider ecosystem.The team values curiosity, depth of analysis, and the ability to translate complex insights for non-technical stakeholders. You will work end-to-end across analytics, measurement, and experimentation, with scope to impact how data is produced, consumed and used across the organisation. Responsibilities • Lead analytics and technical discovery for a core product area • Influence product direction and commercial strategy • Own the end-to-end experimentation process • Mentor other analysts and scientists (no line management) • Support scalable self-serve analytics tools and processes Core skills • SQL: day-to-day user • Python: beneficial but not essential • Visualisation: experience with PowerBI, Looker or Tableau • Familiarity with ETL workflows • Proven autonomy running A/B tests end-to-end (typically 3–5 per quarter), including statistical analysis using Python, SQL packages or third-party platforms such as Optimizely • Strong communication skills, able to work closely with non-technical stakeholders • Commercial mindset with an interest in product demand, behaviour and outcomes To register your interest, please send an up to date CV to roshnibaillie@harnham.com or use the Apply link on this page.

Senior Product Data Scientist - Up to £85k + Benefits | London (Hybrid) A major consumer marketplace is hiring a Senior Product Data Scientist to lead analytics and experimentation across a high-impact product area. You'll work closely with Product, Engineering and ML teams, owning technical discovery, shaping strategy, and driving experimentation at scale.What you'll do<ul><li>Lead analytics for a core product vertical</li><li>Own technical discovery and experimentation frameworks</li><li>Design, run and deeply analyse A/B tests (3-5 per quarter)</li><li>Mentor other analysts (no line management)</li><li>Influence product & business strategy end-to-end</li><li>Enable scalable, self-serve analytics</li></ul>What you'll bring<ul><li>Strong SQL (daily use)</li><li>Python experience (nice to have)</li><li>BI tools (Looker/PowerBI/Tableau)</li><li>Experience with Optimizely or similar testing platforms</li><li>Excellent communication + stakeholder influence</li><li>Hands-on, highly technical, commercially minded</li></ul>Why apply?<ul><li>Up to £85k base</li><li>1 day a week in a modern London office</li><li>Outstanding benefits</li></ul>Perfect for someone who wants technical depth, strategic influence and high ownership-without people management.Find out more and apply via the link below.

Question	Topic	Difficulty	Ask Chance
Boarding Times Bias	Statistics	Medium	Very High
Hundreds of Hypotheses	Statistics	Medium	Very High
Random Bucketing	A/B Testing & Experimentation	Medium	Very High

Harnham Interview Questions

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