British Journal of Educational Psychology (2001), 71, 43–56 Printed in Great Britain © 2001 The British Psychological Society Inattention, hyperactivity and impulsiveness: Their impact on academic achievement and progress C. Merrell* and P.B. Tymms Curriculum Evaluation and Management Centre, University of Durham Background. Children with Attention Decit Hyperactivity Disorder (ADHD) have been found to achieve lower grades at school than their peers. Does this extend to pupils who are apparently exceptionally inattentive, hyperactive or impulsive, but have not been diagnosed as having ADHD? Aims. This study determined the proportion of children who were assessed by their teachers as exceptionally inattentive, hyperactive or impulsive in the classroom. The relationships between these traits, achievement and progress were examined. Sample. The participants comprised 4148 children from a nationally repre- sentative sample of schools in England. Methods. Reading and mathematics achievement of the participants was assessed at the start and end of the reception year, and in year 2. Behaviour was assessed at the end of reception using a rating scale based on the diagnostic criteria for ADHD (American Psychiatric Association, 1994). Results. The proportion of children with exceptional scores on the behaviour rating scale was reported.The reading and mathematics attainment and value- added of children with high scores on the behaviour rating scale were found to be educationally and statistically signicantly lower than children with zero scores. Conclusions. The achievement of children with high scores on the behaviour rating scale replicated previous studies which investigated the achievement of children with ADHD. The behaviour rating scale could be a useful tool for raising the awareness of teachers to young children with severe behavioural problems of inattention, hyperactivity and impulsivity who have not been diagnosed as having ADHD but may nevertheless be at risk of similar outcomes. Some children exhibit inattentive, and perhaps also hyperactive and impulsive behav- iour in the classroom far more frequently and severely than other children of the same age, gender and developmental level.These behavioural characteristics are reected in * Request for reprints should be addressed to Christine Merrell, Curriculum Evaluation and Management Centre, University of Durham, Mountjoy Research Centre 4, Stockton Road, Durham, DHI 3UZ, UK (e- mail: Christine.Merrell@cem.dur.ac.uk).