Wechsler Preschool and Primary Scale of Intelligence - Test Format

Test Format

The Wechsler Preschool and Primary Scale of Intelligence consist of 14 subtests. They are designated as one of three types: core, supplemental, or optional. The core subtests are required for the computation of the Verbal, Performance, and Full Scale IQ. The supplemental subtests provide additional information about cognitive abilities or can be used as replacement for inappropriate subtests. The optional subtests provide additional information about cognitive functioning but cannot be used as replacements for core subtests.

• Block Design - while viewing a constructed model or a picture in a stimulus book, the child uses one- or two-colour blocks to re-create the design within a specified time limit.
• Information - for Picture Items, the child responds to a question by choosing a picture from four response options. For Verbal Items, the child answers questions that address a broad range of general knowledge topics.
• Matrix Reasoning - the child looks at an incomplete matrix and selects the missing portion from 4 or 5 response options.
• Vocabulary - for Picture Items, the child names pictures that are displayed in a stimulus book. For Verbal Items, the child gives definitions for words that the examiner reads aloud.
• Picture Concepts - the child is presented with two or three rows of pictures and chooses one picture from each row to form a group with a common characteristic.
• Symbol Search - the child scans a search group and indicates whether a target symbol matches any of the symbols in the search group.
• Word Reasoning- the child is asked to identify the common concept being described in a series of increasingly specific clues.
• Coding - the child copies symbols that are paired with simple geometric shapes. Using a key, the child draws each symbol in its corresponding shape.
• Comprehension - the child answers questions based on his or her understanding of general principles and social situations.
• Picture Completion - the child views a picture and then points to or names the important missing part.
• Similarities - the child is read an incomplete sentence containing two concepts that share a common characteristic. The child is asked to complete the sentence by providing a response that reflects the shared characteristic.
• Receptive Vocabulary - the child looks at a group of four pictures and points to the one the examiner names aloud.
• Object Assembly - the child is presented with the pieces of a puzzle in a standard arrangement and fits the pieces together to form a meaningful whole within 90 seconds.
• Picture Naming - the child names pictures that are displayed in a stimulus book.

The WPPSI–III provides Verbal and Performance IQ scores as well as a Full Scale IQ score. In addition, the Processing Speed Quotient (known as the Processing Speed Index on previous Wechsler scales) can be derived for children aged 4 – 7 years 3 months, and a General Language Composite can be determined for children in both age bands (2 years 6 months – 3 years 11 months & 4–7 years 3 months). Children in the 2 years 6 months – 3 years 11 months age band are administered only five of the subtests: Receptive Vocabulary, Block Design, Information, Object Assembly, and Picture Naming.

Quotient and Composite scores have a mean of 100 and a standard deviation of 15. Subtest scaled scores have a mean of 10 and a standard deviation of 3. For Quotient and Composite score:

This is true for most Wechsler Scales with the exception of the WIAT-III.