Test types

The WISC

The standard individually administered cognitive test for children aged roughly six to sixteen, and the instrument behind most gifted and special-education decisions.

What it is and who takes it

The Wechsler Intelligence Scale for Children covers ages six to sixteen and follows the same structure as the adult version, adapted for children. The current edition is the fifth.

Children are usually referred rather than volunteered: by a school investigating a learning difficulty, by a gifted programme requiring evidence, by a clinician assessing a developmental concern, or by parents seeking documentation for a placement.

For younger children there is a separate instrument, the WPPSI, covering roughly ages two and a half to seven.

What it measures

The same five indices as the adult scale: verbal comprehension, visual–spatial, fluid reasoning, working memory and processing speed, each built from subtests and each reported on the standard 100/15 scale.

The profile across indices is often the point of the assessment. A child with strong verbal comprehension and weak processing speed presents very differently in a classroom from a child with the reverse pattern, and the full-scale score alone would hide both.

What happens in the session

Sixty to ninety minutes, one-to-one, usually in a single sitting with breaks. The psychologist works through subtests in a standard order, building rapport first and stopping each subtest once the child reaches a ceiling.

Children are not told how they did during the session, and are not meant to be. A child who works out that they are failing items will change how they approach the rest, which is precisely the variance the standardised procedure exists to control.

Parents are typically not in the room. This is not secrecy; a parent's presence reliably changes a child's behaviour and the norms assume they are absent.

Reading the report

A useful report contains the full-scale score with its confidence interval and percentile, each index with its own interval, a statement about which differences between indices are meaningful, behavioural observations, and recommendations tied to the reason for referral.

A report that is a number and a label is not useful, and it is reasonable to ask for more. The recommendations are the part that changes anything about the child's week.

Two cautions. Scores before about age six are noticeably less stable than later ones, and a single early score is a weak basis for any long-term decision. And a full-scale score can be misleading where index scores diverge sharply — the average of two very different numbers describes neither.

Gifted identification and the threshold problem

Most gifted programmes use a cut-off around the 98th percentile, which is about 130. Some use 125. Some use a group-administered test such as the CogAT for screening and reserve individual testing for borderline cases.

The threshold is administrative. Nothing changes about a child between 129 and 131, and a confidence interval of plus or minus five points means a child near the line will fall on either side of it depending on the day.

Identification based on a single test score is also known to under-identify children from backgrounds with less test familiarity, which is why multiple-source identification — cognitive measure, achievement measure, teacher observation, work samples — has become standard guidance. More for parents.

Should you prepare a child?

Make sure they have slept, eaten and used the bathroom. Tell them it is a set of puzzles and games, that some will be hard on purpose, and that nobody is expected to get everything right. That is the whole of legitimate preparation for most children.

Coaching on specific item types is a different matter. It raises the score without raising the ability, which risks placing a child in a programme they will then struggle in — an outcome worse for the child than not being placed. Several school systems have moved towards less coachable instruments in response.