IQ has been shown to be positively correlated with success – with ‘success’ defined in various ways – in many studies.

For example, IQ is the best available predictor of job performance.

Predictor Validity Predicting Job Performance Ratings Cognitive test score .53 Biographical data .37 Reference checks .26 Education .22 Interview .14 College grades .11 Interest .10 Age -.01 Source: Hunter and Hunter 1984

Another example, one criterion for ‘success’ is avoiding poverty. As the data reported below show, being dull or very dull is a huge disadvantage in trying to avoid poverty. Normal whites are three times as likely to be in poverty as very bright whites.

  **White Poverty by Cognitive Class**  **Cognitive Class       Percentage in Poverty**  **I Very bright                2**  **II Bright                    3**  **III Normal                   6**  **IV Dull                     16**  **V Very dull                 30**  **Overall average              7**  Data from the NLSY and reported in *The Bell Curve*, page 132.

Another example: the probability that a white woman will go on welfare – after controlling for marital status and poverty – is highly negatively correlated with IQ. It’s only modestly negatively correlated with parental socioeconomic status. In other words, if ‘success’ is defined as not going on welfare within a year of having a child, white women are better off having a high IQ than rich parents (see _The Bell Curve pages 195-96 for documentation).

Percentage of Mothers Who Went on AFDC Within a Year of First Birth Cognitive Class 1 I Very bright 4 II Bright 12 III Normal 21 IV Dull 55 V Very Dull 12 Overall average Data from the NLSY and reported on page 194 of The Bell Curve.

  • References:**

Herrnstein, R.J., and Murray, C. The Bell Curve: Intelligence and Class Structure in American Life

Hunter, J.E., and Hunter, R.F. 1984. Validity and utility of alternative predictors of job performance. Psychological Bull. 92:72-98