Dr. Colin D. Elliott, PhD was for 20 years the tutor and director of the course for professional educational psychologists at Manchester University (UK). Since 1973, he has been involved in research and development on the British Ability Scales, the Differential Ability Scales (the U.S. version of the BAS), BAS 2 and now DAS-II. His other research and publications have focused on individual differences in children's temperament and personality and specific learning difficulties. He moved to the United States in 1992. Dr Elliott is a fellow of the American Psychological Association (APA) and British Psychological Society. He is also an active member of National Association of School Psychologists (NASP).