Editing G factor (psychometrics) (section)

===Academic achievement===

The predictive validity of ''g'' is most conspicuous in the domain of scholastic performance. This is apparently because ''g'' is closely linked to the ability to learn novel material and understand concepts and meanings.<ref name="Jensen 1998, 270"/>

In elementary school, the correlation between IQ and grades and achievement scores is between .60 and .70. At more advanced educational levels, more students from the lower end of the IQ distribution drop out, which restricts the range of IQs and results in lower validity coefficients. In high school, college, and graduate school the validity coefficients are .50–.60, .40–.50, and .30–.40, respectively. The ''g'' loadings of IQ scores are high, but it is possible that some of the validity of IQ in predicting scholastic achievement is attributable to factors measured by IQ independent of ''g''. According to research by [[Robert L. Thorndike]], 80 to 90 percent of the ''predictable'' variance in scholastic performance is due to ''g'', with the rest attributed to non-''g'' factors measured by IQ and other tests.<ref>Jensen 1998, 279–280</ref>

Achievement test scores are more highly correlated with IQ than school grades. This may be because grades are more influenced by the teacher's idiosyncratic perceptions of the student.<ref>Jensen 1998, 279</ref> In a longitudinal English study, ''g'' scores measured at age 11 correlated with all the 25 subject tests of the national [[GCSE]] examination taken at age 16. The correlations ranged from .77 for the mathematics test to .42 for the art test. The correlation between ''g'' and a general educational factor computed from the GCSE tests was .81.<ref name="brody2006">Brody 2006</ref>

Research suggests that the [[SAT]], widely used in college admissions, is primarily a measure of ''g''. A correlation of .82 has been found between ''g'' scores computed from an IQ test battery and SAT scores. In a study of 165,000 students at 41 U.S. colleges, SAT scores were found to be correlated at .47 with first-year college grade-point average after correcting for range restriction in SAT scores (the correlation rises to .55 when course difficulty is held constant, i.e., if all students attended the same set of classes).<ref name="sackett2008"/><ref>Frey & Detterman 2004</ref>