Flynn J R
Am J Ment Defic. 1985 Nov;90(3):236-44.
The definition of mental retardation offered by the American Association on Mental Deficiency refers to an IQ of approximately 70 or below. This is identical to the Wechsler criterion of a test performance two standard deviations (SDs) below the population mean. In fact, Wechsler tests have not supplied such a criterion, rather they have deviated from it by anything from .27 to a full SD. Having done without such a criterion for 40 years, we should consider exchanging it for one that is fixed in time and whose external validity is attested to by an accumulated body of evidence.
美国智力缺陷协会给出的智力迟钝定义指智商约为70或更低。这与韦氏标准相同，即测试成绩比总体均值低两个标准差（SDs）。事实上，韦氏测试并未提供这样一个标准，而是偏离了该标准，偏差范围从0.27到整整一个标准差。在没有这样一个标准的情况下已经过去了40年，我们应该考虑用一个在时间上固定且其外部效度有大量累积证据证明的标准来取而代之。
