The investigators designed the Child-Caregiver Interaction Observation Scale（CCIOS）to assess social communication behaviors, stereotyped behaviors for children with autism spectrum disorder(ASD) via a 20-min video of interactions between a caregiver and a child. The original CCIOS coding scheme consists 23 items. The score range for each item is 0-4, with higher scores being indicative of more atypical behavior. The aim of the study is to determine items for inclusion in the final CCIOS coding scheme through exploration of item correlations, establish the cutoff score of CCIOS for ASD and evaluate the reliability and validity of CCIOS. The reliability evaluation include test-retest reliability and inter-rater reliability. DSM-5 criterion is used as the gold standard. Validity is assessed by determining the correlation and consistency between CCIOS and DSM-5 criterion.

The investigators designed the Child-Caregiver Interaction Observation Scale（CCIOS）to assess social communication behaviors, stereotyped behaviors for children with autism spectrum disorder(ASD) via a 20-min video of interactions between a caregiver and a child. The original CCIOS coding scheme consists 23 items. The score range for each item is 0-4, with higher scores being indicative of more atypical behavior. The investigators conduct this study to determine items for inclusion in the final CCIOS coding scheme through exploration of item correlations, establish the cutoff score of CCIOS for ASD and evaluate the reliability and validity of CCIOS.

It is of importance to accurately distinguish children with ASD from those with Global Developmental Delay (GDD) and Language Disorder (LD) without ASD, sometimes, it's very difficult in children with mental ages below 2 years. This differentiation has strong implications for treatment recommendations and may also inform long-term prognosis. In this study, The investigators planned to recruit 60 children with ASD and 60 children with GDD/LD aged from 18 months to 48 months. The reliability evaluation include test-retest reliability and inter-rater reliability. DSM-5 criterion is used as the gold standard. Validity is assessed by determining the correlation and consistency between CCIOS and DSM-5 criterion.

Inclusion Criteria:

• The ASD/GDD/LD diagnosis is made based on the criteria of ASD/GDD/LD in Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5) ;
• Age 18 months - 48 months;

Exclusion Criteria:

• Visual, audi-tory and physical disabilities

ASD/GDD/LD children are from development behavior clinic