The WISC-IV provides a full-scale IQ (a measure of global general intelligence), a general ability index (based on perceptual reasoning and verbal comprehension), and a cognitive proficiency index (based on processing speed and working memory).

When there is a large discrepancy between the GAI and CPI, the full-scale IQ is not reflective of the child's true abilities and should not be computed. However, a large discrepancy may be indicative of certain conditions such as ADD, ADHD, and so on and so forth.

A high cognitive proficiency index is pertinent to the child's academic achievement as it frees up the potential for higher problem-solving; a child with a high GAI may be proficient at understanding a problem and the means of solving it, but holding that information in his or her head and manipulating it to achieve a correct result is dependent on the magnitude of his or her CPI.

That being said, a common personality trait among gifted students is a need for precision and accuracy. As a result, they will develop slow, meticulous responses to any given mental task. This personality trait will have the tendency to decrease his or her processing speed, and a common profile among gifted people of all ages is high verbal comprehension, perceptual reasoning, and working memory indices, accompanied with a relatively low processing speed index. However, it should be noted that this personality trait also has the tendency to inflate the other three indices on the Wechsler Battery, and so the full-scale IQ is still reliably measured by the test.