Extremely Low

A score below 70 on a standardised IQ test, combined with significant deficits in adaptive functioning, meets the diagnostic criteria for intellectual disability (ID) under DSM-5 and ICD-11. However, an IQ score alone is not sufficient for diagnosis — adaptive functioning (the ability to manage everyday tasks, social relationships, and independent living) must also be assessed.

About 2.2% of the population scores below 70 on IQ tests, but intellectual disability is typically identified in approximately 1% of the population — the difference reflects that many people who score below 70 do not have significant adaptive deficits.

Online IQ tests — including AurorIQ — are significantly less accurate at the extremes of the score distribution. The questions are designed for the middle range of the bell curve and provide less reliable discrimination at very low or very high scores. A score below 70 on an online test should not be taken as a reliable indicator of intellectual disability.

If you or someone you care for is concerned about cognitive functioning, the correct course of action is a formal evaluation by a licensed clinical psychologist using a standardised, proctored test such as the WAIS-IV or Stanford-Binet 5, followed by an adaptive behaviour assessment.

The terminology around low IQ scores has changed significantly over time. Terms previously in clinical use — "moron," "imbecile," "idiot," and later "mental retardation" — have all been retired in favour of "intellectual disability" (ID) because of the stigma attached to earlier labels. The current preferred terms in clinical and academic settings are "intellectual disability" (DSM-5) or "disorder of intellectual development" (ICD-11).

If this page is relevant to you or someone in your care, the most important message is that IQ is not destiny. People with intellectual disability live rich, meaningful lives, develop skills, form relationships, and contribute to their communities. A number on a test does not define a person.