Resume

T.J. Gaffney

This page contains employment and education details. For non-work projects, see the rest of the site. (Some substantial projects may be excluded due to proprietary information.)

Email: gaffney.tj@gmail.com

Work History

Sr Machine Learning Engineer - Meta (December 2022 - 2025)

I worked on Omnichannel Optimization, which attempts to maximize conversions from multiple channels (online, in-app, offline).

Omni-shopping model

I prototyped our team's model for target omni-shoppers.

2022-2025Link

Incrementality

Setup incrementality experiments for data, and ensembled existing models to drive incrementality.

2022-2025Link

Omni measurement

Wrote scripts to analyze omni-shopping backend tests. Wrote proxies to estimate incrementality.

2022-2025Link

Sr Machine Learning Engineer - Reddit (June 2021 - October 2022)

I worked on Reddit's User Understanding team, whose main task was to features for use in models, primarily recommendations. I created specific features and established patterns for aggregating content features to users and creating user embeddings. This work focused on both batch and streaming pipelines.

User embeddings

Built user embeddings using Collaborative Filtering and user history. Designed pipeline to resolve cold start problem. Proved predictive value in recommendation models.

2021-2022Link

User interests

Aggregates content labels to user level. Project included filtering NSFW, grouping labels, and decaying. I designed and implemented. Batch feature was built with Airflow scheduler calling BigQuery scripts. Streaming feature was built with Flink. Further built User-to-Subreddit mapping using Annoy approximate nearest neighbors.

2021-2022Link

Subreddit depth

Designed and implemented bespoke Markov chain approach to compute average time-to-discover for subreddits. Optimized and parallelized expensive matrix computation for >99% speed up.

2021-2022Link

Brand safety analysis

Built analytics dashboard. Helped change serving pattern to increase ad slots ~8%.

2021-2022Link

User covariates

Covariates are user variables that we control for when analyzing impact of A/B tests. I identified impactful covariates and wrote script to compute these.

2021-2022Link

Software Engineer - Google (May 2018 - June 2021)

I worked for a team called FameBit on YouTube, which facilitates organic ads in YouTube videos. More specifically I'm in a group that deals with matching creators to brands.

Audience sentiment aggregation

For various back-end projects, I've worked with audience sentiment data to aggregate to a channel-level.

2018-2021Link

YouTube channel recommendation

Designed and implemented model to find best YouTube channels for a client, given URL and keywords for brand/campaign.

2018-2021Link

Video view predictor

Utilized monte carlo simulations in a patent pending application to predict views for a pool of channels.

2018-2021Link

Video review pipeline

Developed a UI pipeline to facilitate and automate video reviews.

2018-2021Link

Payments database

Implemented server for CRUD operations (and export/reverse) on a payment table.

2018-2021Link

Contract processing

I did some side work on a project which attempted to automatically process contracts. For my part, I scraped the FCC EDGAR database to find contracts to be used by human and machine labelers.

2018-2021Link

Gaming Consultant - The Innovation Group (Apr 2018 - May 2018)

For a brief period, I consulted with The Innovation Group.

Oceans marketing

Leading up to Oceans Casino's relaunch, I prepared some research on the market segments, and designed their loyalty program.

2018Link

Sports betting market sizing

I conducted surveys and matched to Census data to model demand. I used this in a gravity model to estimate market size of sports betting in states that were considering legalizing.

2018Link

Manager, Marketing Analytics - Pinnacle Entertainment (Apr 2016 - Apr 2018)

I was a manager in a group that analyzed about $500M of marketing budget; as manager, I drove the direction/workflow. We touched many branches of marketing, including direct mail, host program, events/promotions, loyalty program, and advertising. I worked on a wide range of projects, including: Ad hocs; building reports; A/B split testing of DM campaigns; goal-setting for casino hosts; market segmentation; advertising impacts; and test-analyzing survey results.

Ad hoc analyses and reporting tools

Analyses on effectiveness of digital direct mail, Asian play trends, cross-property marketing, and others.

2016-2018Link

Data work

Aggregated player data and joined with the marketing data from many sources and systems.

2016-2018Link

AB testing of DM campaigns

Advised on statistical methodology and developed software to quickly run AB testing and reporting, resulting in an 80% reduction in process time. Reporting included visualizations for drill down decision-making. Created results repository for long-term trend analysis.

2016-2018Link

Casino host target model

Modeled expected hosted players' play. Significant improvement over existing methodology.

2016-2018Link

Marketing segmentation

Designed and aligned market segments from 15 different casinos.

2016-2018Link

Event post forma dashboard

Built a Tableau dashboard to show event KPIs versus benchmarks. Spearheaded initive and achieved wide roll-out to about 60 users at 15 casinos with 1000s of uses per month, becoming most-used workbook in the company.

2016-2018Link

Survey analysis

Performed sentiment analysis on year-end survey results, and communicated results to the company.

2016-2018Link

License bids

Conducted a live game theory experiment to help decide how to bid for gaming licenses.

2016-2018Link

Actuary, Commercial Lines Analytics - Auto-Owners Insurance (Sep 2014 - Apr 2016)

My team built the models for Auto Owners' commercial line products, including TTP, commercial auto, workers comp, and others. My work was divided about equally into three tasks: Data work, modeling, and research. Data work was SQL work to pull data for our models, and the models were large general linear models.

Fraud model

Used an SVM on text to predict fraud from claim notes. This allowed us to automate the work of 15 FTEs.

2014-2016Link

Model packet automations

Reversed-engineered pre-packaged GLM software, allowing us to automatically produce modeling packets. This reduced a day-long project to minutes.

2014-2016Link

Dimensionality reduction

Researched and advised analysts in the company on dimension reduction in auto and credit datasets. We looked into PCA, partial least squares, and lasso regressions.

2014-2016Link

Lifetime value model

Built a customer lifetime value model of our commerical policy data.

2014-2016Link

Commercial auto model

Helped refresh our decade-old commercial auto model, combining two previous models.

2014-2016Link

Presentations

I presented research on Shapley values and family errorwise rates that influenced our modeling techniques broadly.

2014-2016Link

Stats Lecturer - Davenport University (Jun 2015 - Aug 2015)

I thought Intro to Stats at nights one summer while I was an actuary. That semester I redesigned the term project.

Underwriting Actuary - Qualchoice Insurance (Feb 2014 - Sep 2014)

I was the company's only underwriting actuary. My main job was to create and maintain software to renew group insurance policies. Additionally I worked on a number of small and ad hoc projects.

Obamacare updates

Researched to understand how new legislation impacted the way that we priced policies.

2014Link

ICD-9 to ICD-10 migration

Wrote a web scraper to get a ICD-9 to ICD-10 crosswalk.

2014Link

ASO pricing

Priced our new small ASO product using Monte Carlo simulations.

2014Link

Teaching Assistant - Michigan State University (Sep 2011 - Aug 2013)

While in grad school, I thought a dozen classes over six semesters. These classes included algebra, math for education majors, and calculus 2 and 3. As teacher, I taught classes; met with students; wrote and graded tests; and reported grades. In my first year, I won a reward from the department for teaching.

Education

Master's in Mathematics - Michigan State University (Fall 2011 - Summer 2013)

GPA: 3.83

Qualifying exams

Passed qualifying exams on geometry/topology, algebra, and analysis.

2011-2013Link

Teaching award

I won an award for best junior teaching assistant.

2011-2013Link

Bachelor's in Mathematics - University of Nevada, Reno (Fall 2009 - Spring 2011)

GPA: 3.83

Competitve awards

As an undergraduate, I won first place at UNR in each of: The Putnam exam, the Intermountain Mathematics competition, and the university’s Association for Computing Machinery programming competition. My team of three won the designation of meritorious winner in the international COMAP Mathematics Competition in Modeling.

2007-2011Link

Clubs

I participated in a number of clubs, as well as founding UNR's math club and go club.

2007-2011Link