Professor Chang's research has focused primarily on improving large scale assessments, specifically on issues emerged from the K-12 accountability testing. His research interests are broad, encompassing both theoretical development and applied methodologies, including Computerized Adaptive Testing, Differential Item Functioning, Cognitive Diagnosis, and asymptotic properties in IRT. Many of his manuscripts were published in top-tier journals, ranging from very theoretical, such as Annals of Statistics, to very applied, such as Journal of Educational Measurement. He is a past President of the Psychometric Society (2012-2013), a Fellow of American Educational Research Association, and a Fellow of American Statistical Association.

Professor Chang's research has focused primarily on improving large scale assessments, specifically on issues emerged from the K-12 accountability testing. His research interests are broad, encompassing both theoretical development and applied methodologies, including Computerized Adaptive Testing, Differential Item Functioning, Cognitive Diagnosis, and asymptotic properties in IRT.