Wan's research focuses on understanding the developmental processes underlying achievement development in skill-based domains, and using evidence from educational research to improve student success. He has two primary lines of research. One examines skill development, especially math skill development. The other examines factors related to achievement-related choice such as major choice and career choice. Prior to pursuing his Ph.D. in Education, Wan earned a bachelor’s degree in Engineering from Harbin Institute of Technology and a M.S. degree in Developmental and Educational Psychology from Beijing Normal University, China, and worked as an engineer.
Bailey's research interests include mathematical development, individual differences, and longitudinal methods. As a Jacobs Foundation Research Fellow (2019-2021), Bailey is studying the processes underlying the stability of individual differences in youngsters’ mathematical achievements and the medium- and long-term effects of early interventions. He serves as the UCI School of Education’s Faculty Director of Undergraduate Programs.
To determine whether scaling decisions might account for fadeout of impacts in early education interventions, we reanalyze data from a well-known early mathematics RCT intervention that showed substantial fadeout in the two years after the intervention ended. We examine how various order-preserving transformations of the scale affect the relative mathematics achievement of the control and experimental groups by age. Although fadeout was robust to most transformations, we were able to eliminate or even reverse fadeout by emphasizing differences in scores near typical levels of first-graders while treating differences elsewhere as unimportant. Such a transformation lowers treatment effects at preschool age and raises them in first grade, relative to the original scale. The findings suggest substantial implications for interpreting the effects of educational interventions.