Tim Coleman

Google Data Science, Trust and Safety Team

What am I up to right now?

I recently joined the Trust and Safety Team at Google as a Data Scientist! Recently, I completed my first post-PhD position, working as a Postdoctoral Researcher at USC! Additionally, I am continuing to work in my spare time on finsihing up previous academic collaborations. (July 18, 2022)

My Academic Work

I served as a Postdoctoral Researcher at the University of Southern California, working under Jacob Bien on modelling populations of phytopolankton in the ocean with an interest in the broader mission of the CBIOMES project, part of the Simons Foundation.

Before USC, I completed a PhD in Statistics at the University of Pittsburgh, under the mentorship of Lucas Mentch. I primarily worked on developing inferential procedures for statistical learning techniques, and focused on applications of those methods to the environmental sciences. During my PhD studies, I was lucky enough to work at the Air Force Research Lab, Lawrence Livermore National Lab, and most recently at Los Alamos National Lab.

My CV can be found here.


Below are links to my publicly available work:

An F-test for Random Forests - the main focus of my PhD work. The goal is to conduct variable importance by comparing predictive accuracy of different random forests via a permutation test that is able to avoid costly variance estimates by exploiting the structure of random forests.

A Space Weather Paper done with some collaborators at the Air Force Research Lab, where we use a Kalman Filter to fit a dynamic linear model to forecast electron flux levels in the upper magnetosphere.

Covariate Shifted Random Forests - motivated by the problem of forecasting hurricane outages during particularly extreme storms, this work proposes an importance sampling modification to standard random forest models.

Application of Random Forest Inference Procedures to Tree Swallow Migrations - using data from the eBird project, we study the association between seasonal temperature patterns and bird occurrence. Recently published in the Journal of the Royal Statistical Society, Series C.

Recent Talks

I’ve recently presented work, or will be presenting work, at the following venues:



For a collection of errata (small typos that do not rise to the level of a formal errata being published), see this link

About Me

Here I am!

I recieved my Bachelors with majors in Applied Math and Geography from Colgate University in 2016. I was borrn in the UK, grew up in Northern California, and am currently living in LA after having struggled through many winters in Pittsburgh, PA (while still spending some time out in New Mexico.) I love to run (when I’m not actually running, of course), hike, and generally explore wherever I happen to be!