08/19/2026
When the COVID-19 pandemic halted fieldwork in the Amazon, Matthew Stewart pivoted his SEAS Ph.D. from measuring emissions in the rainforest to modeling and machine learning.
Mentored by Vijay Janapa Reddi, he dove into benchmarking datasets, algorithms, and hardware, and began thinking deeply about how AI systems intersect with policy and society. After completing his Ph.D., he stayed on as a postdoctoral researcher, focusing on the societal impacts of AI.
Today, Stewart is a lead AI researcher at Pelago Health, a digital substance use care provider. His work explores whether AI can help people access mental health and substance use support with strong safety guardrails and real clinical oversight. One of his current projects uses human-in-the-loop AI to help clinicians monitor for suicidality and intervene when warning signs appear.
“We're basically exploring this bridging factor of whether you can have an AI that allows people to get the clinical care they need, but with more safety guardrails and clinical oversight than a typical AI agent,” he said. "Because this space still doesn’t have a gold standard for how to do it, we're still trying to feel out exactly what makes the most sense. But we're definitely taking a very safety-cautious approach in the way we're building it.”
His interest in algorithmic accountability led to his award-winning paper “Beyond Explanation: Evidentiary Rights for Algorithmic Accountability,” which analyzed 168 court cases to show how access to evidence affects the ability to contest algorithmic decisions. His vision: a world where people can question and verify automated decisions, rather than simply being told to trust them. https://bit.ly/4cHsutp
