PEAK Pre-Assessments: Preliminary Evidence Establishing Internal Consistency and Construct Validity.

Area of Science:

• Behavior analysis
• Psychometrics
• Developmental psychology

Background:

• The Promoting the Emergence of Advanced Knowledge (PEAK) system is a behavior-analytic tool designed to assess and teach language and cognitive skills.
• Early and accurate assessment is crucial for individuals with developmental disabilities, particularly autism spectrum disorder (ASD).

Purpose of the Study:

• To evaluate the construct validity and internal consistency of the PEAK preassessment.
• To examine the correlations between PEAK preassessment scores and established measures of intelligence, adaptive behavior, age, autism diagnostic instruments, and aggression.

Main Methods:

• The study involved a sample of 18 individuals receiving behavior-analytic assessment in an autism clinic.
• PEAK preassessment total scores were correlated with scores from intelligence scales, adaptive behavior scales, autism diagnostic instruments, and aggression scales.
• Internal consistency was assessed by examining correlations between all modules within the PEAK system.

Main Results:

• PEAK preassessment total scores demonstrated statistically significant positive correlations with measures of intelligence (r = .703, p = .023) and adaptive behavior (r = .618, p = .018).
• No significant correlations were found between PEAK preassessment scores and age, autism diagnostic instruments, or aggression scales.
• All modules within the PEAK system showed statistically significant correlations with each other (p ≤ .001), indicating strong internal consistency.

Conclusions:

• The PEAK preassessment shows promising preliminary evidence of construct validity, correlating well with established measures of cognitive and adaptive functioning.
• The internal consistency of the PEAK system's modules is supported by significant intercorrelations.
• These findings suggest that the PEAK system is a potentially reliable and valid tool for assessing language and cognitive abilities in individuals with autism spectrum disorder.