He understood intelligence to be more of an effect, rather than a cause. The Wechsler tests are based on ten or eleven verbal and performance subtests. Wechsler believed the subtests were collectively capable of yielding important clinical insights that could be used for differential diagnosis as well as measuring a broad range of psychological functioning. In order to determine a meaningful representation of adult intelligence, Wechsler introduced the Deviation Quotient, an IQ computed by considering the individual's mental ability in comparison with the average individual of his or her own age. The aggregate, or global capacity to act purposefully, think rationally, and deal effectively with the environment.
Intelligence is an aspect of the total personality, rather than an isolated entity.