About – Samuel Castillo

“Mathematics is the language in which God has written the universe.” — Galileo Galilei

Resume

Entrepreneur with a passion for turning data-driven insights into tangible business outcomes. In 2021, I founded a startup and earned a spot in the Capital Factory Startup Accelerator, an experience that deepened my commitment to innovation and growth.

My professional journey includes working in actuarial science at Willis Towers Watson and contributing to AI development at Milliman IntelliScript. With over five years in corporate roles and several years as an independent contractor, I bring a versatile and analytical approach to every project.

I love programming in R and was the original author of an open-source R package titled Datasets for Predictive Analytics, a CRAN library that reached more than 1,100 monthly downloads in 2020. That work came out of my own research and hands-on project experience. Over time, my name and authorship were removed from the materials, and the current version of the library substantially reproduces the structure and content of my original contribution without attribution. In my view, that evolution of the package effectively plagiarized the core of my work and took my name off the research.

What I Do

Data Science & Analytics

Predictive modeling, machine learning, large-scale data processing
AI / LLM Engineering

Training LLMs, building AI agents, N8N automation

Professional Experience

Integrated Security Consultants, Inc

AI Solutions Developer

March 2025 - June 2025 (4 months) · Massachusetts, United States
- Trained LLMs to act as virtual tech guides, automating the step-by-step install process for surveillance cameras and security systems.
Pass My Exam, LLC

Product Developer

June 2024 - August 2024 (3 months) · Northampton, Massachusetts, United States
- Recipient of AWS Activate Startups program (Tier 1)
- Built UI/UX materials for AI and Machine Learning
- Developed web applications using AWS
- Built YouTube channel from zero to 50,000+ lifetime views through strategic content development and audience engagement
- Analyzed viewer metrics and engagement data to optimize content performance and channel growth strategies
Expedia Group

Data Analyst

November 2022 - November 2023 (1 year 1 month) · Austin, Texas, United States
- Analyzed large-scale travel data related to flight bookings, vacation rentals, hotels, and car rentals, handling data at scale.
- Architected predictive analytics models processing global travel datasets, encompassing flight bookings, hotel reservations, and vacation rentals.
- Accelerated data workflows from 3 days to hours using AI-tuned Python scripts. This enabled real-time data access.
- Explored datasets from 100+ countries with machine learning. Turned raw numbers into strategic insights that shaped where the company invested next.
- Developed AI agents with Python and R, which successfully performed tasks assigned to them, and addressed complex forecasting challenges, utilizing API get requests and scheduled scripts in PowerShell.
- Safeguarded sensitive customer data following international privacy regulations, ensuring strict compliance.
Pass My Exam LLC

Founder, CEO

November 2019 - May 2022 (2 years 7 months) · Austin, Texas, United States
- Started a business which secured early-stage support with Capital Factory, a leading startup accelerator in downtown Austin Texas that supports hundreds of small businesses and provides top-level business mentoring and resources in Capital Factory University sessions—founder-led masterclasses that translate entrepreneurial theory into real-world tactics.
- Completed a selective 12-week accelerator featuring daily workshops on AI, customer discovery, product-market fit, fundraising, and go-to-market strategy.
- Engineered and maintained a cloud-based data platform hosting predictive analytics models.
- Developed Python-based ETL pipelines for data ingestion and transformation.
- Deployed AWS services including S3, Lambda, and EC2 for cost-efficient computing.
- Mentored junior data engineers and led a team of freelancers.
Boehringer Ingelheim

Data Scientist Contractor

June 2021 - October 2021 (5 months) · Austin, Texas, United States
- Brought on by an agency Data Science Talent Limited, for a contractor with the Animal Health Data team with Boehringer Ingelheim.
- Constructed convolutional neural network (CNN) models in TensorFlow for high-throughput biological data classification in pharmaceutical research applications that accelerated the pharmaceutical discovery timelines by 30%.
- Tested Neural Networks on genomic datasets for COVID-19 antibody vaccine research, demonstrating expertise in healthcare data applications.
- Developed comprehensive animal health databases enabling empirical analysis for veterinary medicine applications.
- Orchestrated SQL and Python/R for data pipeline engineering, creating clean, structured datasets optimized for machine learning model training.
- Managed large streaming datasets from search analytics, TV metrics, retail sales, and promotions. Supported strategic sales initiatives by identifying key trends in the healthcare sector.
Keywell.ai

Reporting Analyst Contractor

May 2021- July 2021 · Austin, Texas
- Prepared data for AI/ML Initiatives using Python, improving data quality for advanced analytics.
- Helped a medical team track eating disorder treatment by building a data reporting pipeline using AWS Athena, RDS, Glue, and S3 that turns EHR data into a self-service reporting dashboard.
- Improved database design by refactoring a 600 line SQL script into 50 lines of code using inner joins, subqueries, case when statements, and lookup tables.
Milliman IntelliScript

Data Scientist

January 2019 - April 2020 (1 year 4 months) · Greater Chicago Area
- Trained AI and ML models on large scale data.
- Utilized distributed computing to efficiently handle large-scale data processing, optimizing system performance and enabling seamless integration.
- Engineered data pipelines for healthcare datasets containing 10+ million individual records, achieving 13% improvement in predictive model performance through advanced feature engineering.
- Integrated medical datasets using standardized healthcare coding systems (ICD, CPT, DRG), creating AI models for Fortune 500 health care companies.
- Leveraged distributed computing frameworks for processing 200TB healthcare workloads, achieving 50% cost reduction while maintaining data integrity.
- Ensured strict compliance with healthcare data security regulations including HIPAA and GDPR, implementing zero-trust infrastructure protocols.
- Developed privacy-preserving AI algorithms generating anonymized group-level insights while protecting individual patient data confidentiality.
Willis Towers Watson

Actuarial Analyst

February 2018 - January 2019 (1 year) · Greater Boston Area
- Used Rescue, Radar, and Emblem to conduct reserving studies.
- Assisted account managers for international airlines & hotels.
- Optimized big data framework and reduced costs by 50%.
- Subject matter expert on predictive analytics tools.
- Designed predictive models for customer behavior analysis serving major healthcare and travel clients, providing financial projections and strategic insights.
- Optimized big data architecture processing on 200TB scale, reducing operational costs by 50% through distributed computing implementation.
- Coordinated international AI/ML initiatives across multiple countries, delivering pre-trained models requiring client-specific fine-tuning and customization.
Milliman

Actuarial Intern

October 2017 - January 2018 (4 months) · Greater Boston Area
- Updated reserving analysis for property and casualty insurance companies.
- Performed rate-filing reviews for New England carriers.
- Captive insurance feasibility studies for firms located in Bermuda.
Blue Cross Blue Shield of Massachusetts

Data Science Intern

June 2017 - August 2017 (3 months) · Boston
- Participated in research on health insurance plan design using analytics and machine learning.
- Presented at end-of-internship event about how people with low back pain can reduce the need for surgery.
- Attended cross-disciplinary mentoring sessions with actuaries and data scientists.

Education

University of Massachusetts, Amherst

Bachelor's Degree, Mathematics

2015 - May 2017

Major in Mathematics

Academic Tutor · September 2016 - May 2017 (9 months) · Amherst, MA

Part-time peer tutoring (flexible schedule)
Led group discussions (1-4 people) using whiteboards and laptops
Classes Tutored: Algebra, Calculus, Linear Algebra, Finance, Differential Equations, Astronomy

Actuarial Exams & Certifications

I have successfully passed the following Society of Actuaries (SOA) / Casualty Actuarial Society (CAS) exams — each one of the most rigorous professional credentialing programs in the world (graduate-level difficulty).

Exam P — Probability Theory Passed
Exam PA — Predictive Analytics (top-tier machine-learning exam) Passed
Exam MFE / 3F — Models for Financial Economics Passed
Exam STAM — Short-Term Actuarial Mathematics Passed
Exam FM / 2 — Financial Mathematics Passed

Undergraduate Honors Student — University of Massachusetts Amherst
Graduated with honors in Mathematics while completing the majority of the actuarial exam track.

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What I Do

Data Science & Analytics

AI / LLM Engineering

Professional Experience

Integrated Security Consultants, Inc

Pass My Exam, LLC

Expedia Group

Pass My Exam LLC

Boehringer Ingelheim

Keywell.ai

Milliman IntelliScript

Willis Towers Watson

Milliman

Blue Cross Blue Shield of Massachusetts

Education

University of Massachusetts, Amherst

Actuarial Exams & Certifications

Featured Content