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Leiter International Performance Scale – Third Edition (Leiter-3)

The Leiter International Performance Scale – Third Edition (Leiter-3; Roid, Miller, Pomplun, & Koch, 2013) is a standardized, individually administered, nonverbal test designed to assess cognitive functions in children, adolescents, and adults ages 3 to 75 years. The Leiter-3 includes two groupings of subtests: the Cognitive Scales that measure fluid intelligence and the Attention and Memory Scales.


The Leiter-3 IQ score is not significantly impacted by language skills or by experiences (educational, social, family). The Leiter-3 is designed for use with individuals who are non- English-speaking, hearing impaired, speech impaired, cognitively delayed, or on the autism spectrum.


Author (yr) Age Range (yrs) Method of Administration/Format Approx. Time to Administer Subscales
Leiter International Performance Scale – Third Edition (Leiter-3) Roid, Miller Pomplun, & Koch (2013) 3-75+

Individually administered, norm-referenced measure of nonverbal cognition

10 subtests in 2 domains, Cognitive Scales (Fluid Intelligence) and Attention and Memory Scales.

Yields subtest and composite scores given in scaled scores, percentiles, and age equivalents. Also yields Growth Scores to indicate small improvements in people with significant cognitive disabilities.

20-45 min.

Sequential Order; Form Completion; Classification and Analogies; Figure-Ground; Matching/Repeated Patterns (optional); Forward Memory; Reverse Memory; Attention Sustained; Attention Divided; Nonverbal Stroop

Availability: Western Psychological Services,


Author (yr) Sample Size Topic(s) Addressed Outcome
Tsatsanis, Dartnall, Cicchetti, Sparrow, Klin, & Volkmar (2003) 26 - Age Range: 4-16 years Concurrent validity

Researchers examined the relationship of the Leiter-R with the Leiter on a group of individuals with autism. The mean Leiter IQ score was not statistically different from the Leiter-R Brief IQ (t(21) = 1.37, p = .18) and Leiter IQ or Leiter Full IQ (t(21) = 0.37, p = .71).

Scores did not significantly differ between the Leiter-R Brief IQ and Leiter IQ (t(21) = 1.37, p = .18) and Leiter R Full IQ (t(21) = .37, p = .71).

Classification into levels of functioning was examined. High agreement was found (kappa = .69, p < .0001)
Author (yr) Sample Size Topic(s) Addressed Outcome
Grondhuis & Mulick (2013). 1,071 - Age Range: 3-12 years Validity

Differences in scores on the SB5 and Leiter-R were compared for a sample of children with autistic disorder and PDD-NOS. Results suggest that they are not equivalent measures of cognitive functioning when administered to individuals with ASD. As a result, depending on the measure used, misclassification of intellectual functioning could occur. Key results are summarized below.

A significant difference in scores were found between the Leiter-R and the SB5 (F(1,40) = 58.99, p < .001). The Leiter-R was, on average,

22.45 points higher than the SB5. The mean score on the Leiter-R was 87.11 while the mean on the SB5 was 64.66.

Diagnostic differences were found. Autistic disorder (Leiter-R mean IQ = 79.42; SB5 mean = 59.12); PDD-NOS (Leiter-R mean = 96.61;

SB5 mean 71.52). Differences were not significant (F(1,40) = 3.16, p < .08). The discrepancy was significantly greater (Leiter-R IQ scores higher than SB5) in preschool children compared to those in grade school (F(1,40) = 4.88, p < .033.

Scores on the Nonverbal domain of the SB5 (mean = 70.40) were significantly lower than the Leiter-R full-scale composite (mean = 87.12); t(46) = 7.751, p <.001.

Scores on the Verbal domain of the SB5 (mean = 62.00) was significantly lower than the Leiter- R total score (mean = 87.24); t(44) = 10.020, p <.001.

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