About Me
My name is Wendy (Ran) Wei. I’m an ML Engineer specializing in search, recommendation, and personalization systems — currently building ranking, relevance, and GenAI-powered search at Airbnb.
I grew up in China and got my bachelor’s degree in Mathematics & Statistics from Zhejiang University, with an exchange year studying statistics at Uppsala University in Sweden. From there I went to The Ohio State University for my PhD in Statistics (minor in Computer Science), working with Dr. Elizabeth Stasny and Dr. David Sivakoff on network sampling and estimation theory. During grad school I interned as a Data Scientist at Twitter, and was part of the team that won the 2013 Capital One National Data Analytics/Modeling Competition.
That Twitter internship turned into a full-time role, and I’ve spent the decade since building large-scale ML systems across social, e-commerce, and marketplace platforms: personalizing the Explore Tab at Twitter/X, working on ads quality at Pinterest, building video recommendation systems at Facebook/Meta, founding TigerLab AI (an open-source toolkit for LLM safety evaluation) and teaching Python along the way, leading search retrieval and relevance work — including early GenAI/LLM initiatives — at Coupang, and now working on ranking, relevance, and personalization at Airbnb.
Alongside the day job, I write. I’m the author of Advanced Retrieval-Augmented Generation: Bridging Large Language Models and Knowledge Graphs (Wiley-IEEE Press), which bridges LLMs and knowledge graphs to help build AI systems that hallucinate less and reason better, and Data Science: Methods and Practice (数据科学：方法与实践, China Machine Press), a textbook spanning statistics, machine learning, and their applications in search, recommendation, and NLP. I also hold a couple of patents on detecting anomalous behavior on social platforms, and I keep a running Conference Tracker and occasional Tech Notes from talks and workshops I find interesting.
If any of that overlaps with what you’re working on, I’d love to hear from you — find me on LinkedIn, GitHub, or Twitter/X.
Blogs
I keep a small corner of the site for writing and side projects — tech notes from talks and workshops I attend, plus tools I’ve built for fun, like a conference-deadline tracker, an I Ching hexagram-casting app, and a French vocabulary trainer.