Senior Experimentation Scientist

Preply; Greater London; On-site; GBP 50,000 - 70,000; Full time

Job summary

A growing Ed-Tech company in Greater London is looking for a data analyst to enhance their experimentation framework and support decision-making within product and marketing teams. Candidates should have a strong background (5+ years) in data science, proficiency in SQL and Python, and excellent communication skills. This role offers opportunities for personal development, collaboration with diverse teams, and a competitive financial package, contributing to impactful learning experiences worldwide.

Benefits

Generous monthly lesson allowance

Learning & Development budget

Competitive financial package with equity

Qualifications

• 5+ years of experience in the data science & analytics field.
• Experience in product or marketing experimentation is preferred.
• Solid SQL and Python skills are necessary.
• Good understanding of statistical analysis concepts.
• Fluent English communication skills required.

Responsibilities

• Research and implement new approaches for hypothesis testing.
• Analyze and quantify the impact of marketing development.
• Support engineers in building high-quality data pipelines.
• Collaborate with teams to measure the impact of budget changes.

Skills

Data analysis

SQL

Python (NumPy, Pandas, SciPy)

Statistical analysis

Problem-solving

Communication skills

Tools

Airflow

Redshift

Looker

Amplitude

Job description

This job is brought to you by Jobs/Redefined, the UK's leading over-50s age inclusive jobs board.

We power people's progress.

At Preply, we're all about creating life-changing learning experiences. We help people discover the magic of the perfect tutor, craft a personalized learning journey, and stay motivated to keep growing. Our approach is human‑led, tech‑enabled - and it's creating real impact. So far, 90,000 tutors have delivered over 20 million lessons to learners in more than 175 countries.
Meet the team!

We A/B test most of our changes on production, both product and technical, before scaling it to all customers. The Experimentation Squad owns the whole infrastructure and the framework that are used to make those business‑vital decisions.

We define the framework rules, including the overall evaluation criterion, set of target metrics, available test types: student‑side, tutor‑side, clustered; frequentist, Bayesian, interleaving; superiority, non‑inferiority. We analyze performance of the experimentation program using multiple holdout groups and push product management in the directions, which will improve its results. Finally we're in charge of improving the company's experimentation culture and education, and keeping institutional memory.

Our Data Team is dedicated to empowering top‑quality decision‑making. Do you want to know how? Visit our Tech Radar to learn about the technologies we use at Preply!

What you'll be doing

• Unlock the potential of product and marketing teams by researching and implementing new approaches for hypothesis testing (clustering, interleaving, geolift,..);
• Identifying and designing value‑adding insights solutions, leveraging data to optimize our strategy;
• Establish credibility and quality of the experimentation framework;
• Quantify the impact of product and marketing development and distinct initiatives in order to identify growth opportunities and help top management in prioritizing Preply's roadmap;
• Level up the experimentation culture across the company;
• Support engineers to build and maintain high‑quality data pipelines;
• Collaborate with product teams to help them tackle technical issues with A/B testing.
• Collaborate with marketing teams to measure the impact of changes in budget relocation.

What you need to succeed

• Extensive experience in the data science & analytics field (5+ years' experience at least);
• Experience in product or marketing experimentation and desire to dive deeper into the sphere and research best industry practices to build state‑of‑the‑art experimentation in Preply;
• Strong curiosity, problem‑solving, and problem‑finding skills;
• Solid SQL hands‑on experience, and strong knowledge of Python (NumPy, Pandas, SciPy);
• Good understanding of statistical analysis concepts such as p‑value, null hypothesis, and confidence interval;
• Eagerness to take responsibility for systems that directly impact the company's decision‑making process;
• Passion for analyzing data to inform decisions, measuring and monitoring;
• Willingness to educate colleagues (doing knowledge‑sharing sessions);
• Excellent written and verbal communication skills. Fluent English is a must.

Nice to have

• Experience applying advanced experimentation - Bayesian testing, causal impact analysis;
• Knowledge of Airflow, Redshift (or any other Data Warehouse DBs - Snowflake, BigQuery..)
• Knowledge of Looker, Amplitude, Databricks, or other BI tools.

Why you'll love it at Preply

• An open, collaborative, dynamic and diverse culture;
• A generous monthly allowance for lessons on Preply.com;
• Learning & Development budget, including time off for your self‑development;
• Competitive financial package with equity, and leave allowance;
• The opportunity to unlock the potential of learners and tutors through language learning and teaching in 175 countries (and counting!).

#LI-AG1

Our Principles

• Care to change the world - We are passionate about our work and care deeply about its impact to be life changing.
• We do it for learners - For both Preply and tutors, learners are why we do what we do. Every day we focus on empowering tutors to deliver an exceptional learning experience.
• Keep perfecting - To create an outstanding customer experience, we focus on simplicity, smoothness, and enjoyment, continually perfecting it as every detail matters.
• Now is the time - In a fast‑paced world, it matters how quickly we act. Now is the time to make great things happen.
• Disciplined execution - What makes us disciplined is the excellence in our execution. We set clear goals, focus on what matters, and utilize our resources efficiently.
• Dive deep - We leverage business acumen and curiosity to investigate disparities between numbers and stories, unlocking meaningful insights to guide our decisions.
• Growth mindset - We proactively seek growth opportunities and believe today's best performance becomes tomorrow's starting point. We humbly embrace feedback and learn from setbacks.
• Raise the bar - We raise our performance standards continuously, alongside each new hire and promotion. We build diverse and high‑performing teams that can make a real difference.
• Challenge, disagree and commit - We value open and candid communication, even when we don't fully agree. We speak our minds, challenge when necessary, and fully commit to decisions once made.
• One Preply - We prioritize collaboration, inclusion, and the success of our team over personal ambitions. Together, we support and celebrate each other's progress.

Diversity, Equity, and Inclusion

Preply.com is committed to creating an inclusive environment where people of diverse backgrounds can thrive. We believe that the presence of different opinions and viewpoints is a key ingredient for our success as a multicultural Ed‑Tech company. That means that Preply will consider all applications for employment without regard to race, color, religion, gender identity or expression, sexual orientation, national origin, disability, age or veteran status.