James received his B.S. from the Ohio State University in Mathematics and Physics, and his Ph.D. from Carnegie Mellon University in the joint program in Statistics and Machine Learning. He was a postdoctoral researcher in the Mathematics department at UC San Diego before he joined the Statistics department at UC Davis as an Assistant Professor. He became an Associate Professor in 2021, worked at Amazon Search as a Senior Applied Scientist, and has been at Duolingo as a Staff AI Research Scientist since 2022. His research lies at the intersection of statistics and machine learning, and he has over 50 published works in statistics journals, machine learning conferences, and scientific journals. This main area of research is in non-parametric statistics and machine learning and their applications to recommendation systems, epidemiology, astronomy, transportation science, and education. At Duolingo, he is developing Machine Learning powered test assessment for the Duolingo English Test, a high-stakes English language proficiency test.