Leiter International Performance Scale - THIRD Edition (Leiter-3)

Purpose: Evaluate nonverbal cognitive, attentional and neuropsychological abilities in typical and atypical children, adolescents and adults.

Age: 3–75+ years

Time: 20–25 minutes

The Leiter International Performance Test – Third Edition (Leiter-3) evaluates nonverbal cognitive, attentional and neuropsychological abilities.  

Its engaging, nonverbal format makes it ideal for use of individuals with Autism, Speech/Language Disorders, as well those with English as a second language. The Leiter-3 provides an IQ score, as well as percentile and age-equivalent scores for each subtest.

The Leiter-3 includes a number of new measures. Overall efficiency and utility of the Leiter-3 has been increased by combining Leiter-R subtests, and removing items with similar difficulty levels (based on Leiter-R data). Through this process, the number of subtests has been reduced from 20 to 10. The streamlined Leiter-3 provides improved assessment of Fluid Reasoning and Attention/Memory.

New features of Leiter-3

• Block and Frame format, for more accurate assessment of individuals with neurological disorders.
• Decreased number of subtests, increasing overall efficiency and utility of the instrument.
• A neuropsychological subtest, a Nonverbal Stroop Test has been added.
• All new Attention-Divided subtest, with greater reliability and ease of use
• Psychometric studies show the Leiter-3 to have exceptional fairness for all cultural and ethnic backgrounds
• Re-designed to accommodate individuals with a wide range of cognitive and physical disabilities. Blocks are lightweight, colourful, non-toxic and choke-safe, with rounded corners to prevent harm to either the subject or examiner.

Leiter-3 Subtests

Cognitive Scales (Fluid Intelligence)

Unlike other IQ tests, the Leiter-3 emphasises fluid intelligence, the truest measure of an individual’s innate cognitive abilities.

• Sequential Order (SO)
• Form Completion (FC)
• Classification and Analogies (CA)
• Figure Ground (FG)
• Matching/Repeated Patterns (M/RP)- optional   

Attention and Memory Scales

Attention and Memory subtests enhance interpretation of the global IQ score, by providing valuable diagnostic indicators regarding the score on the Cognitive portion of the Leiter-3. They also distinguish individuals with ADHD, LD or neuropsychological impairments, from typically-functioning individuals.

• Forward Memory (FM)
• Attention Sustained (AS)
• Reverse Memory (RM)
• Nonverbal Stroop (NS)
• Attention Divided (AD)

Examiner Rating Scale

The Social-Emotional Examiner Rating Scale gathers information about the individual's:

• Attention
• Organisation Skills
• Impulse Control
• Activity Level
• Anxiety
• Energy and Feelings
• Mood Regulation
• Sociability
• Sensory Reactivity

Scoring

The Leiter-3 provides individual subtest, and numerous composite scores, that measure intelligence and discrete ability areas. These scores identify strengths and weaknesses in individual skills, as well as skill sets. Percentile and age-equivalent scores are provided.

Growth Scores are provided for all domains, enabling professionals to measure small, but important, cognitive shifts within a skill set, particularly important for children with cognitive disabilities. Tracking these shifts allows professionals, educators and parents to see the improvement (growth) across time, irrespective of age-based standard scores.