In my line of work, we use IQ testing often to help us diagnose the "gifted" child who perhaps has been unjustly labeled as a "troubled" child.
An IQ Test is a process that involves the child sitting in a quiet room with an examiner for about 1 1/2 hours. The child is asked a variety of verbal questions, is asked to look at pictures and puzzles, asked to repeat certain things, and do a few paper and pencil activities. For the most part, it does not feel like a school test and the vast majority of gifted kids want to keep the testing going because they feel challenged and engaged.
But why is IQ testing important and what does it help us ascertain overall?
First, it is good to know where your child "lives" intellectually, as the higher a child's IQ is, the more different they are from their "peers" and thus, the more accommodations they may need at school, programs, and at home. There is a lot of variability even within the gifted spectrum, meaning that gifted kids at the higher end need more accommodations and individuation than gifted kids whose intelligence is closer to advanced learners - smart kids who generally do well in school.
Another important reason for IQ testing is that it assesses several important aspects of cognitive functioning. IQ tests look at verbal reasoning abilities, visual-spatial reasoning, working memory, and processing speed. Many children, and gifted children in particular, often have "asynchronous development" meaning that their abilities are very uneven. Understanding whether someone is high in verbal processing, yet low on visual can have significant impacts on informing their teacher, yourself, and the child on how they learn best. Further, gifted children are often high on reasoning abilities and relatively or substantially lower on working memory and processing speed, causing academic underachievement and frustration. It is important to know if this is the case so accommodations can be put in place to help a smart child show what they know.
Test results tell parents and teachers how advanced a child's thinking may be and therefore how much differentiation they need from the regular curriculum which is set up for the "average" child. Test results also tells us a child's learning and processing strengths and weaknesses so parents and teachers can tailor their communication and teaching to the child's strengths and set up accommodations and interventions for identified weak areas.
This testing benefits the gifted child in that it helps the primary people in the child's life - parents and teachers - better understand their thinking, learning, achievement, social, and emotional needs. As mentioned earlier, the farther the child is from "normal" the less "normal" they usually act and feel, and the more they need differentiation in the aforementioned areas.
What age should your child be tested at? This question does not have an absolute answer. Ideally, the older a child is, the more information we can get both because the child is more developmentally mature and the tests themselves can tell us more. The WISC-IV, the most commonly used IQ test starts at age 6 - which is a good time to get a child tested. That being said, many children benefit from earlier testing to identify their strength and weakness profile. In this case, we can give a full pre-school intelligence at age 4, and a partial version at age 2 1/2.
Dr. Dan Peters, Ph.D., is co-founder of the Summit Center (http://summitcenter.us/), which provides psychological and educational assessments and counseling for children and adolescents, specializing in the gifted, creative, and twice-exceptional.