Archive

Archive for October 2025

Heterogeneous treatment-effect estimation with S-, T-, and X-learners using H2OML

Motivation

In an era of large-scale experimentation and rich observational data, the one-size-fits-all paradigm is giving way to individualized decision-making. Whether targeting messages to voters, assigning medical treatments to patients, or recommending products to consumers, practitioners increasingly seek to tailor interventions based on individual characteristics. This shift hinges on understanding how treatment effects vary across individuals, not just whether interventions work on average, but for whom they work best. Read more…

Stata commands to run ChatGPT, Claude, Gemini, and Grok

I wrote a blog post in 2023 titled A Stata command to run ChatGPT, and it remains popular. Unfortunately, OpenAI has changed the API code, and the chatgpt command in that post no longer runs. In this post, I will show you how to update the API code and how to write similar Stata commands that use Claude, Gemini, and Grok like this: Read more…