Issues Related to Obtaining Intelligence Quotient-Matched Controls in Autism Research

BACKGROUND: Intelligence Quotient (IQ) is considered to be an index of global cognitive functioning and has traditionally been used as a fulcral measure in case-control studies in neuro-developmental disorders such as autism. AIM: The aim is to highlight the issues of “matching for IQ” with controls in autism research. MATERIALS AND METHODS: Percentile scores on the Coloured Progressive Matrices of 20 children with autism in the age range of 5 to 12 years have been graphically compared with 21 age matched typically developing children. RESULTS AND CONCLUSIONS: The percentile scores of the so-called high functioning children with autism from special schools were well below that of typically developing children. There are many challenges when using IQ in case-control studies of autism. Alternative approaches need to be considered.