2.3.1. Overall Cognitive Ability

Stanford-Binet, Fifth Edition (SB-5) [35]. Overall IQ was measured using the abbreviated battery IQ (ABIQ) to describe the cognitive abilities of the sample and examine associations with social measures. The SB-5 is a standardized measure of cognition and the ABIQ includes one nonverbal (Fluid Reasoning) and one verbal (Knowledge) subtest. The ABIQ is strongly correlated with the full-scale IQ in samples of children with a neurodevelopmental disorder [36], and reliability is also high for the ABIQ (*r* = 0.85–0.96) [35]. Deviation scores were used in this study to eliminate floor effects (deviation scoring procedures described in [32]). The ABIQ deviation scores are an estimate of the full-scale deviation scores. Negative scores are possible using deviation scoring and represent raw scores that for a participant's age are more than 3.33 standard deviations below the mean [32].
