WISC®-V Test Preparation Book The Wechsler Intelligence Scale for Children®/WISC® is used to assess intelligence in children aged 6 to 16. It consists of 16 primary and five complementary subtests. The WISC®-V assessment takes between 50 and 65 minutes to complete. The purpose of the test is to determine whether or not the child is gifted, as well as the student's cognitive strengths and weaknesses.