Senior Data Scientist Job at Bark

Senior Data Scientist

Bark

Location:
Spain

Category:
IT - Software Development

Contract Type:
Not provided

Salary:

Not provided

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Job Description:

We are hiring a Senior Data Scientist to join our Data and Insight team in a newly created role. This is a product-facing, experimentation-led machine learning position focused on building high impact models, designing robust simulations and driving measurable business outcomes through rigorous testing and evaluation. You will report to the Lead Data Scientist and sit within the Data and Insight function. The role is centred on algorithm design, model evaluation and statistical experimentation focussing on product impact. You will work across multiple areas of the business, translating complex product and commercial challenges into well-structured analytical frameworks, testable hypotheses and high quality predictive models. This role requires someone who is comfortable moving from exploratory analysis through proof of concept to controlled experimentation and risk assessment.

Job Responsibility:

Design, develop and refine machine learning models ranging from linear and logistic regression through to tree-based methods, ensemble approaches and advanced algorithms
Develop proof of concepts and translate exploratory insights into structured modelling approaches
Design and execute statistical offline simulations to validate modelling approaches prior to live experimentation
Plan, implement and analyse controlled A/B tests, ensuring statistical robustness and clear interpretation of results
Define success metrics aligned to business objectives and ensure appropriate evaluation frameworks are in place
Analyse model performance using appropriate metrics such as precision, recall, ROC-AUC, log loss, calibration measures and model-specific metrics
Identify potential sources of bias, data leakage and experimental confounding, and proactively mitigate associated risks
Work closely with Product, Engineering and other stakeholders to prioritise opportunities and ensure models deliver measurable value
Communicate complex modelling concepts, trade-offs and experimental results in a clear and accessible way to both technical and non-technical audiences
Contribute to raising the overall standard of modelling practices within the team

Requirements:

3 to 4 years of experience building, evaluating and iterating on machine learning models using large and complex data sets
Strong academic background in Statistics, Mathematics, Computer Science or a related quantitative discipline
Deep understanding of statistics, machine learning and experimental design principles
Demonstrated experience running A/B tests, designing offline validation strategies and interpreting experimental outcomes
Strong grasp of model evaluation metrics and the ability to select appropriate performance measures based on business context
Strong programming skills in Python with experience using libraries such as NumPy, Pandas and related tools for data manipulation and analysis
Experience working with cloud-based data infrastructure such as BigQuery and AWS services including S3 and SageMaker
Experience using Jupyter notebooks for exploratory analysis, modelling and communicating findings
Ability to move comfortably between high level problem framing and detailed quantitative analysis
Strong product orientation with experience collaborating closely with cross-functional teams
Excellent written and verbal communication skills, with the ability to explain technical concepts clearly and confidently

Nice to have:

Experience working in a two-sided marketplace or similarly complex environment
Familiarity with ranking metrics and optimisation techniques in high volume marketplace environments
Practical experience experimenting with large language models and designing evaluation frameworks for generative AI use cases
Understanding of MLOps principles and the model lifecycle, including deployment, monitoring and retraining considerations

What we offer:

25 days of paid holiday, with extra days added at 3 and 5 years of service
Fully remote working, plus up to 20 days each year to work from anywhere in the world
An annual Learning & Development budget of €550 to spend on courses, training, or other resources that support your professional development
Access to Oliva, a leading mental health and wellbeing platform, offering personalised support when you need it
A €250 allowance towards essential home office technology to help you stay connected and productive

Additional Information:

Job Posted:
March 01, 2026

Employment Type:

Fulltime

Work Type:

Remote work

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