Senior Applied Data Scientist | NDA

GT; Warszawa; On-site; PLN 180,000 - 260,000; Full time

Job summary

GT is seeking a Senior Applied Data Scientist to advance entity matching at scale. You will develop and test ML, embeddings, and LLM-based approaches for matching complex business records across multiple data sources.

The role emphasizes model quality, experimentation, and evaluation, with engineering partners helping productionize successful ideas. You'll explore foundation-model techniques to improve matching while keeping costs and latency in check, working closely with data and software

Qualifications

• 5–8 years of relevant experience in Data Science or Applied Machine Learning.
• Strong Python and SQL skills.
• Experience with embeddings, semantic similarity, LLMs.
• Hands-on training of supervised and unsupervised models.
• Knowledge of neural networks and transformer architectures.
• Proficiency with ML frameworks such as TensorFlow, PyTorch, PyCaret.
• Experience retraining a taxonomy classifier in production.
• Experimental judgment with baselines, metrics, and error analysis.
• Ability to explain model behavior to engineering and business partners.

Responsibilities

• Develop ML, embedding, and LLM-based approaches to matching entities.
• Improve handling of messy data, including multilingual records.
• Develop scoring and ranking to distinguish matches from duplicates.
• Evaluate AI techniques balancing accuracy, scalability and cost.
• Design scalable approaches considering model usage and compute cost.
• Collaborate with data and software engineering to productionize models.
• Define evaluation methods for match quality and benchmarks.
• Build trusted benchmark sets for model comparison.
• Explore LLM-assisted review for scalable benchmarking.

Skills

Applied Data Science

Python & SQL

Embeddings & LLMs

Neural networks & transformers

ML frameworks (TensorFlow, PyTorch, Py

Experimentation & evaluation

Engineer collaboration

Tools

TensorFlow

PyTorch

PyCaret

Job description

GT was founded in 2019 by a former Apple, Nest, and Google executive.GT’s mission is to connect the world’s best talent with product careers offered by high-growth companies in the UK, USA, Canada, Germany, and the Netherlands.

On behalf of our client, GT is looking for a Senior Applied Data Scientist interested in developing and testing new ML, embedding, and LLM-based approaches to solve complex data matching problems at scale.

About the Client

Our client is a leading global management consultancy known for tackling some of the world’s most complex business challenges. With a focus on strategy, transformation, and performance improvement, the firm partners with major organizations across industries to drive lasting impact.

About the Role

We are looking for a Senior Applied Data Scientist to improve how entity resolution is performed at scale.

You will develop and test new ML, embedding, and LLM-based approaches for matching complex business records across multiple data sources.

The work is centered on model quality, experimentation, and evaluation; engineering partners will help productionize successful approaches.

A key part of the role is exploring how newer foundation-model techniques can improve matching quality while remaining practical and scalable for very large datasets.

Responsibilities:

Develop better ways to match company records

• Build new ML, embedding, and LLM-based approaches for matching entities

• Improve how the system handles messy data, including name variations, aliases, domains, websites, firmographic attributes, multilingual records, and data hierarchies.

• Develop scoring and ranking approaches to distinguish accurate matches from duplicates, similar-looking records, and unrelated entities.

• Evaluate and implement AI and machine learning techniques to improve matching quality while considering accuracy, scalability, and cost.

• Design approaches that can operate efficiently at scale, taking model usage and computational cost into consideration.

Improve evaluation, experimentation, and match quality

• Define and improve methods for evaluating match quality, including precision, recall, false positives, false negatives, confidence, coverage, and manual review effort.

• Assist in building trusted benchmark sets that allow us to compare new models against the current matching engine before production rollout.

• Explore LLM-assisted review and validation to assess matching performance and benchmark more scalable approaches.

• Turn ambiguous matching problems into clear hypotheses, experiments, metrics, and recommendations.

Partner with engineering to bring successful ideas into production

• Work closely with data engineering and software engineering teams to turn promising prototypes into production-ready matching logic.

• Provide engineering partners with clear model specifications, evaluation results, expected behavior, edge cases, and rollout requirements.

• Help determine the most appropriate matching techniques based on data characteristics, confidence levels, and cost considerations.

• Continuously evaluate matching performance, investigate regressions, and recommend improvements to models and matching logic.

• Clearly communicate technical tradeoffs related to matching performance, scalability, cost, latency, explainability, and operational considerations.

Essential knowledge, skills & experience:

• 5–8 years of relevant experience in Data Science, Applied Data Science, Applied Machine Learning, or a similar role.

• Strong applied ML fundamentals, with hands-on experience building and evaluating models on real data.

• Excellent Python and SQL skills.

• Practical experience with embeddings, semantic similarity, LLMs, or related AI techniques.

• Hands-on experience training supervised and unsupervised models, including classification and NLP tasks.

• Working knowledge of neural network and transformer architectures.

• Proficiency with common ML frameworks such as TensorFlow, PyTorch, and PyCaret.

• Experience retraining a taxonomy classifier or maintaining classification models in production.

• Experimental judgment: able to define baselines, metrics, test sets, and error analysis that show whether quality improved.

• Ability to explain model behavior, tradeoffs, and edge cases clearly to engineering and business partners.

Nice-to-have:

• Experience with entity resolution, record linkage, deduplication, or similar matching problems.

• Experience with ranking, similarity scoring, retrieval, clustering, or candidate generation.

• Experience applying LLMs or embeddings to business problems where cost and scale matter.

• Exposure to large-scale data platforms such as Spark, Snowflake, Databricks, or BigQuery.

• Familiarity with company, domain, website, firmographic, or other business-entity data.

Interview Steps:

1. GT interview with Recruiter

2. Technical interview

3. Final interview