Mara Legner

About Mara Legner

I\'m a problem solver at heart. In the past few years I\'ve taken on a lot of home renovation work which means doing a lot of pre-planning and research, making a ton of decisions on sizes/finishes/colors, dealing with unforeseen issues on the fly, and realizing that nothing is ever level, square, or plumb. I also enjoy traveling and a big component is figuring out logistics of where to go, how to get there, where to stay, things to do, and what to pack. I also love all types of puzzles: jigsaw, crossword, Wordle, Sudoku (3 time UW Sudoku Master champion).Throughout my career I\'ve applied this problem solving ability to a wide variety of industries including energy, utilities, aviation, and ratings and reviews. I enjoy researching models and statistical approaches, data wrangling and cleaning, testing and training models, putting models into production, tracking model performance, and iterating as needed. I love solving problems with data but data has limitations, so I also place high value on business stakeholder and SME input, non-quantitative metrics, and keeping humans in the loop.I have experience with all of the following:Large Language Models (LLMs), Generative AI, Deep Learning, Neural Networks, Natural Language Processing (NLP), Machine Learning, Sentiment Analysis, Regular Expressions (RegEx), Python, SQL, PySpark, Amazon Web Services (AWS), Google Cloud Platform (GCP), Hugging Face, H2O Studio, Snowflake, dbt, Github, Tableau, Time Series (ARIMA), SAS

Experience

1. Principal Data Scientist

   Duke Energy Corporation

   Apr 2025 — Present

   Built and optimized 41 machine learning models (linear regression, XGBoost) for feeder-level energy forecasting, each achieving <5% SMAPE• Detected outliers in energy usage by applying clustering methods (DBSCAN, Isolation Forest, OPTICS, LOF) • Coded and productionalized SMAPE and MAPE calculations at the single and three phase feeder levels across the entire service area

Education

• University of Wisconsin-Madison

  Bachelor of Science (BS), Chemical and Biological Engineering

  2006 — 2010

• UCLA

  Master of Financial Engineering

  2013 — 2014

Skills

• Analysis
• R
• Chemical Engineering
• Management
• Technical Writing
• Data Analysis
• Python
• Financial Modeling
• Matlab
• Sas Programming
• Process Simulation