Data Scientist

Lingaro; Polska; On-site; PLN 90,000 - 150,000; Full time

Job summary

Lever, Inc. in Poland is seeking an experienced data scientist to build ML solutions for forecasting and customer analytics, turning business problems into data-driven production models.

You will work closely with business stakeholders to frame problems and define success metrics. The role emphasizes end-to-end modeling, feature engineering, model validation, and deployment support, with opportunities for senior-level pre-sales involvement.

Qualifications

• Commercial experience with various classical data science and ML models (e.g. decision trees, ensemble-based tree models, linear regression).
• Solid knowledge of customer analytics concepts or advanced forecasting.
• Model hyperparameter tuning.
• Model validation frameworks.
• Experience translating business requirements into technical plans, data processing, feature engineering, and model evaluation.
• Previous analytical-role experience supporting business is a plus.
• Fluency in Python, basic working knowledge of SQL.
• Knowledge of DS/ML libraries.
• Solid experience in one cloud platform (Databricks or GCP or Azure).

Responsibilities

• Work on end-to-end classification and forecasting use cases: framing, data prep, model development, evaluation, and basic deployment support.
• Explore and clean data; perform EDA to understand data and flag quality issues.
• Engineer features for tabular and time-series data.
• Train, validate, and tune standard ML models (e.g. logistic regression, tree-based models, gradient boosting, simple neural nets, classical time-series models).
• Evaluate models with metrics tied to business KPIs.
• Build visualizations and reports to present results to stakeholders.
• Collaborate with data/environment engineers to deploy models (batch scoring, APIs, monitoring).
• Document data sources, assumptions, and experiments in notebooks/reports/wikis.
• Translate business problems into technical goals and define success metrics.
• Pre-sales activities at senior consultant level.

Skills

Python

SQL

ML modeling

Forecasting

Feature engineering

MLOps

Data visualization

R

Education

Bachelor's degree in CS/Math/Statistics

Master's preferred

Tools

Databricks

GCP

Azure

scikit-learn

PyTorch

Job description

Our team is delivering business solutions with Machine Learning and Data Science often turning them into scalable platforms including non-trivial and innovative solutions in the space of Forecasting and Customer Analytics often leveraging cutting-edge Causality frameworks. Example projects in this area: Next Best Offer/Action, propensity modeling, churn modeling, forecasting of demand and sales, revenue growth management, etc. This role requires close collaboration with business stakeholders, and the ability to understand their problems and translate them into machine learning ones.

Tasks:

• Work on end-to-end classification and forecasting use cases: problem framing, data preparation, model development, evaluation and basic deployment support (e.g. demand forecasting, churn prediction).
• Explore and clean data; perform EDA to understand data and flag data quality issues.
• Engineer features for tabular and time-series data.
• Train, validate, and tune standard ML models (e.g. logistic regression, tree-based models, gradient boosting, simple neural nets, classical time-series models).
• Evaluate models with appropriate metrics that have impact on business KPIs.
• Build clear visualizations and concise reports to present model results and insights to business stakeholders.
• Collaborate with data engineers and AI engineers to bring models into production (batch scoring, APIs, models monitoring, dashboards).
• Document data sources, modeling assumptions, and experiment results in a reproducible way (notebooks, reports, wikis).
• Business understanding and translating problems into technical goals by defining success metrics, auditing data feasibility, and aligning stakeholder expectations.
• Pre-sales activities (at senior consultant level).

Requirements:

• Commercial experience with various classical data science and Machine Learning (ML) models (e.g. decision trees, ensemble-based tree models, linear regression etc.).

• Solid knowledge of customer analytics concepts or advanced forecasting.

• Model hyperparameter tuning.

• Model validation frameworks.

• Experience with business requirements gathering, transforming them into technical plan, data processing, feature engineering, models evaluation.

• Previous experience in an analytical role supporting business will be a plus.

• Fluency in Python, basic working knowledge of SQL.

• Knowledge of specific DS/ML libraries.

• Solid experience in one of the cloud computing platforms (Databricks or GCP or Azure).

What Will Set You Apart:

• Understanding of Causal machine learning.
• Experience in working with big data and distributed environments would be a plus.
• Commercial experience proven by multiple successful projects in the areas of forecasting would be a big plus.
• Experience with OOP in Python.
• Experience with MLOps.
• Familiarity with other languages R, Scala would be a plus.

General:

• Basic computer programming skills and familiarity with programming concepts.
• Strong business acumen.
• Experience with deep learning, reinforcement learning or other advanced modeling concepts in Classical Data Science problems.
• Ability to come up with creative solutions to address customer problems.