M. Brent Donnellan is Professor of Psychology at Michigan State University. He investigates research topics at the intersections of personality psychology, psychological assessment, and developmental psychology. He currently serves as the Senior Editor for the Personality section of Collabra: Psychology and as an Associate Editor for Advances in Methods and Practices in Psychological Science. His current research efforts focus on personality trait development, the assessment of well-being and self-esteem, and methodological tools and practices to improve psychological science.