Jens Leerssen
Data Engineer
Missoula, Montana, United States
Summary
👤
Senior🎓
Top SchoolJens Leerssen is a pragmatic Data Engineer with 10 years of experience building resilient data warehouses and automated pipelines, currently shaping analytics at Interwell Health from Missoula, Montana. He combines strong SQL and R skills with software engineering practices to align messy, documentation-sparse data into scalable ETL and Airflow-driven workflows that serve clinical, financial, and operational stakeholders. At Cricket Health he architected an enterprise research reporting database and wrote SQL generators that translated design docs into production pipelines, accelerating onboarding of new payors and sources. Jens applies data science and ML pragmatically to mitigate fraud and risk, with hands-on work refactoring legacy Redshift pipelines and improving data quality across merged healthcare entities. An active maintainer on community projects, he’s contributed backend data-loading and integrity fixes to the popular py4e geodata module, reflecting a focus on reliable data ingestion. With a background spanning clinical trials, biotech, education, and finance, he pairs quantitative rigor with a knack for simplifying complex data lifecycles.
10 years of coding experience
7 years of employment as a software developer
Software Engineering, Software Engineering at Hack ReactorDiplome (with Distinction): Business/Commerce Economics French Language and Civilization, Diplome (with Distinction): Business/Commerce Economics French Language and Civilization at Université Paris-SorbonneBachelor of Arts (BA) Psychology (Experimental and Quantitative Studies of Human Behavior); Anthropology, Bachelor of Arts (BA) Psychology (Experimental and Quantitative Studies of Human Behavior); Anthropology at Vanderbilt University
French, Spanish, Japanese
Stackoverflow
14,639reputation
4.5mreached
89answers
14questions
r
top-1%
amazon-s3
top-5%
csv
top-5%
dplyr
top-5%
python
top-5%
pandas
top-5%
Github Skills (21)
database-api10
sqlite10
python10
r10
databases10
dataframe10
database10
pandas9
visual-studio-code9
amazon-s39
dplyr9
merge9
code-formatting9
csv9
courses-resource8
Programming languages (6)
Github contributions (5)
csev/py4e
May 2016 - Sep 2016
Web site for www.py4e.com and source to the Python 3.0 textbook
Role in this project:
Back-end Developer
Back-end DeveloperContributions:13 commits, 4 PRs, 1 comment in 3 months
Contributions summary:Jens primarily contributed to the project by making changes related to data loading, database interactions, and code formatting within the `geodata` module. Their work involved removing deprecated functions, standardizing whitespace, and spell-checking. They also addressed issues related to testing output by reverting previous commits. The commits suggest a focus on maintaining code quality, data handling, and ensuring the integrity of the data loading process.
pythonweb-siteltitextbookpython-3
GroupOut/descriptions
Jul 2018 - Aug 2018
Descriptive information about Deals; including their Merchants, Locations, and Categories
Contributions:28 PRs, 172 pushes, 26 branches in 22 days
merchantsdealsdescriptivefinancelocations
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