John Chester

Tick Heatmap: Community-Powered Bayesian Prediction Engine with CDC & NOAA Priors, HHS Grant Finalist

• Designed, built, and shipped TiCK Heatmap; a live, community-powered tick-encounter and Lyme disease-prevalence tracking platform as sole engineer, spanning a serverless AWS backend (CDK, Lambda, Aurora Serverless v2, DynamoDB) and a React/Vite frontend; the product became the company’s central pitch for a $1M HHS TOPxHHS Tech Sprint grant that advanced to final-stage review
• Built an empirical-Bayes hierarchical Bayesian engine (Poisson-Gamma sighting-density and Binomial-Beta disease-prevalence conjugate models) with multi-level geographic pooling, design-effect weighting for within-submission correlation, and a tick-selection bias correction; enforced privacy-by-design with physically separated PII/incident data stores and zip-only geocoding

Social Media Management Agent

• Designed and deployed a low-code social media comment-management agent (SocBot: n8n, Google Sheets, Claude API) that fetches, analyzes, and drafts replies to 1K+ monthly comments across YouTube, Facebook, and Instagram, saving 15 working hours/month at under $10/month in inference cost
• Created automated weekly reporting using Python and GitHub Actions (cron job with failsafes), pulling data from Shopify and Amazon APIs and posting formatted summaries directly to Slack for weekly standups; used Plotly for trend visualizations

Automated Financial Dashboard

• Built Claude Skills loaded with data dictionaries and modular ETL scripts so the CEO could run ad-hoc analytics requests conversationally, producing interactive dashboard artifacts; saved 1-2 hrs/week of manual data collection while increasing flexibility

Customer Intelligence Insights

• Connected Zigpoll (post-purchase survey) and OuterSignal (customer profiling) via MCP; extracted the ten most common consumer sentiments from Zigpoll history (pointing to product skepticism post-purchase), informing a marketing education push
• Used OuterSignal’s customer-network data conversationally with Claude to develop business strategy, including a proposed expansion into the hospitality rural B&B market with 3-5 specific outreach targets identified

• Guided data-driven negotiation strategies for a $2.3B healthcare portfolio across key healthcare systems, physician groups, and ancillary facilities throughout New England, boosting Cigna’s competitive market position by 1.7%
• Engineered Python dashboards with data storytelling and customizable visualizations for high-stakes contract negotiations, driving savings, improving price transparency, and enhancing cost prediction; adopted nationwide
• Developed and modeled over 35 deals with hospital systems delivering $21M in savings above market expectations
• Leveraged patient and sales data using SQL to create dynamic models which increased planning efficiency by 20%
• Achieved more favorable contract terms in 65% of negotiations completed, for a projected savings of $6.4M
• Evaluated 8 hospital systems for Fee-For-Value programs, shifting 14% of dollars to a risk-sharing arrangement

• Negotiated high-value healthcare contracts with leading hospital institutions including Mount Sinai Health System and Hospital for Special Surgery, both strengthening Cigna’s network and restructuring existing agreements
• Spearheaded surgery center renegotiation efforts in the NYC region, achieving $1.8M savings over one year
• Constructed and executed competitive analysis strategies for hospitals, securing favorable terms in 80+% of deals

• Managed over 10 projects with a team of 15, ensuring timely and efficient completion of each project, while leveraging advanced analytics to optimize processes and increase overall project savings by 15%
• Led the termination process, coordinating across Aetna to ensure regulatory-compliant communications to 350K+ patients