The chapters you have read so far have looked at various approaches for understanding and measuring intelligence. Our focus in this chapter is on the predictive value of measures of general cognitive ability. We write as applied psychologists whose work focuses on the operational use of tests for making decisions about whom to select for admission in higher education contexts and whom to select into jobs in employment contexts. We note that work in these contexts uses the terminology “general cognitive ability” (GCA), rather than “intelligence,” and we use that terminology throughout the chapter.