Company leader
Zachary Ziegler
Co-founder and CTO
OpenEvidence
Zachary Ziegler is co-founder and chief technology officer of OpenEvidence, whose AI search engine gives doctors answers drawn from medical research, with a citation for each claim. He left a Harvard machine learning doctorate to start it after his brother-in-law's leukemia treatment showed him how doctors were getting at a vast body of medical knowledge.
Researching Language Models at Harvard
He was working on a PhD in machine learning at Harvard, in Alexander Rush's natural language processing lab, with a National Science Foundation Graduate Research Fellowship. In 2021 he teamed up with Daniel Nadler.
Watching His Brother-in-Law's Treatment
His brother-in-law was 22 when he went through treatment for leukemia, and he is now in remission. "It was really eye-opening to me," Ziegler said. "There's this enormous amount of complexity, but the way doctors are accessing it is literally leafing through a textbook."
Co-founding OpenEvidence
He and Nadler founded OpenEvidence in November 2021, and he leads the technical work behind its search product. In July 2025 OpenEvidence launched DeepConsult, which uses reasoning models to connect findings across different studies, a tool he likened to giving a physician a team of MD-PhDs who research a topic while the physician does other work.