Brian Riordan is a senior research scientist in the AI Research Labs at ETS, where he leads the research and development of machine learning and natural language processing (NLP) for automated content analysis in educational applications, including the c-raterTM automated scoring system. He was the ETS principal investigator on the NSF-funded project, Supporting Teachers in Responsive Instruction for Developing Expertise in Science (STRIDES), focusing on improving automated analysis of student writing in STEM. He has authored more than 35 publications in NLP, machine learning, education, and cognitive science. He regularly serves as a reviewer for top conferences and journals in NLP and education. Prior to joining ETS, he was a senior research scientist at Aptima, Inc., where he led research efforts for organizations including DARPA, the Office of Naval Research, and the Air Force Research Laboratory. He received his Ph.D. in linguistics and cognitive science from Indiana University.