Mental retardation refers to significantly below-average intelligence. Mental retardation is categorized according to scores on tests that determine intelligence quotient (IQ) and other tests.
| Author | Jan Nissl, RN, BS |
| Editor | Susan Van Houten, RN, BSN, MBA |
| Associate Editor | Tracy Landauer |
| Primary Medical Reviewer | Renée M. Crichlow, MD - Family Medicine |
| Specialist Medical Reviewer | Siobhan M. Dolan, MD, MPH - Reproductive Genetics |
| Last Updated | May 29, 2006 |