About Me

Hi, I’m Stephen, and I work on data and ML systems—primarily in real estate, for some reason :)

I’m currently leading the Pricing and Valuations Applied Science team at Opendoor.

Some things I’ve done

• Multiple ship of theseus rewrites of the OVM codebase (OVM being the valuation model powering all of Opendoor's pricing). Each one leading to the model being faster to train, cheaper, and more performant and stable https://x.com/shrisha/status/2002046356161216715.
• Migrated the core valuation model to be a Transformer (think homes as tokens)
• Built (or rebuilt) many of the core components going into pricing, including valuations, home price appreciation, and hedonic home price indices, and many more.

Before that, I was the first data hire at Better Mortgage, where I worked on a whole bunch of stuff: building the analytics reporting infrastructure and competitor pricing web crawlers, working on price optimization models, and having a lot of fun with survival models and RNNs (before Transformers were cool). I eventually ended up leading the Acquisitions and Capital Markets Data Science team.

Writings

• Competing Process Hazard Function Models for Player Ratings in Ice Hockey
• Tackling Conversion With Survival Models And Neural Networks

You can find me on GitHub and LinkedIn, or email me at stphnma@gmail.com.