Senior Data Scientist – AdTech & Healthcare (f/m/x)

Sii Poland; Kraków; On-site; PLN 210,000 - 270,000; Full time

Benefits offered by this job

Centre of internal trainings

Many experts you can learn from

Profit sharing

Regular integration events and trips

Comfortable and well-equipped offices

Job summary

Sii Poland is seeking a skilled ML/AI researcher in Kraków to design and implement probabilistic methods for entity linking and matching across large healthcare datasets. You will train and monitor production ML models, extract signals from diverse data sources, and build scalable analytics pipelines.

Ideal candidates have 5+ years of experience with Python data-science, ML libraries, and SQL for Snowflake/BigQuery/Databricks, plus strong English.

Qualifications

• Minimum 5 years of experience in training and monitoring ML models for production use.
• Experience with ML engineering, including ETL processes over large datasets and data-quality monitoring.
• Expertise in Python data-science and ML libraries like scikit-learn, PyTorch, LightGBM, SpaCy, and Hugging Face.
• Practical experience in probabilistic methods for entity linking, matching, imputation, scoring, and evaluation.
• Strong SQL skills for distributed warehouses such as Snowflake, BigQuery, or Databricks.
• Advanced level of English.

Responsibilities

• Measuring existing model performance and identifying improvements.
• Owning the design of new methodologies and training next-gen models for scalability.
• Extracting entities and sparse attributes from heterogeneous sources.
• Designing probabilistic entity linking and matching across large healthcare datasets.
• Exploring graph technologies and graph theory.
• Building and owning analytics data stores, evaluation, and monitoring pipelines.

Skills

5+ years experience

Python data-science

ML libraries

Probabilistic methods

SQL for warehouses

English proficient

Tools

Snowflake

BigQuery

Databricks

scikit-learn

PyTorch

LightGBM

SpaCy

Hugging Face

Job description

Tired of building yet another chatbot POC? Do you want to train ML models that bring real monetary value and run at a billion-scale? Do you feel like introducing a brand-new probabilistic methodology for a real-world problem?
We build the AI-powered operating system for healthcare marketing - programmatic advertising, data intelligence, patient affordability and AI-enabled engagement for the life sciences industry.
We are looking for a person who knows how to design and implement statistical methods to extract signals from large, messy, real-world datasets and use them for prediction. Everything we build on top of that, from audience reach to specialty insight to measurement, is only as good as your layer.

Your tasks

• Measuring existing model performance and finding ways to improve it
• Owning the design of the new methodology and training the next-gen model for increased predictive power, sample efficiency, and scalability to large datasets
• Extracting unique entities and sparse attributes from heterogeneous sources – both structured and unstructured
• Designing and implementing probabilistic entity linking & matching across multiple large healthcare datasets
• Exploring graph technologies and graph theory
• Building and owning an analytics data store, evaluation, and monitoring pipelines

Requirements

• Minimum 5 years of experience in training and monitoring ML models for production use
• Experience with data and ML engineering, including ML-facing ETL processes over very large datasets and data-quality monitoring
• Expertise in Python data-science and ML libraries like scikit-learn, PyTorch, LightGBM, Splink, spaCy, and Hugging Face
• Practical experience in probabilistic methods for entity linking, matching, imputation, scoring, and evaluation
• Strong command of SQL for distributed warehouses such as Snowflake, BigQuery, or Databricks
• Advanced level of English

Nice to have

• Experience with graph technologies such as Neo4j, Amazon Neptune, Stardog, or similar platforms
• Familiarity with Graph Machine Learning concepts, including community detection, Graph Neural Networks (GNNs), and graph embeddings
• Exposure to AI-powered development tools such as Cursor AI, Claude Code, or equivalent solutions
• A proactive mindset with a willingness to take ownership of deliverables and contribute to product direction

Job no. JOB-C3836
Sii ensures that all hiring decisions are made solely on the basis of qualifications and competence. We are committed to equal and fair treatment of all, regardless of legally protected characteristics. At Sii, we promote a diverse and inclusive work environment, in full compliance with applicable anti-discrimination laws.

Benefits For You

• Great Place to Work
• Solid financial situation
• Contracts with the biggest brands
• Centre of internal trainings
• Many experts you can learn from
• Open and accessible management team
• Profit sharing
• Passion Sponsorship program
• Regular integration events and trips
• Comfortable and well-equipped offices
• MySii app
• Medical care