Dr. Georgios Sideridis is a Senior Survey Methodologist at Boston Children’s Hospital and Assistant Professor of Pediatrics at Harvard Medical School. He received his Ph.D. in Developmental and Child Psychology from the University of Kansas and did postdoctoral work at the Aristotle University of Thessaloniki. Dr. Sideridis supports with his work on methods and statistics the Division of Developmental Medicine and the Department of Psychiatry at BCH. His research interests lie in (a) the determination of measurement invariance in instruments related to achievement and aptitude, and, (b) evaluating the effects of systematic measurement error on individuals’ scores.