Table 2.

Outcome measure categories based on the outcomes used in the included studies

Category	Outcome measure
Social outcomes (social interaction and communication skills)	Test of Adolescent Social Skills Knowledge _ Revised (TASSK), Friendship Qualities Scale (FQS), Mutual Engagement, NEPSY-II, Positive facial expression, Quality of Play Questionnaire (QPQ), Quality of Socialisation Questionnaire (QSQ), Social inquiries, Social interaction observation system, (SIOS), Social Motivation and Competencies Scale (SMCS), Social preference, Social Skills Improvement Scale (SSIS), Social Skills Rating System (SSRS), Sociometrist nomination, The Contextual Assessment of Social Skills (CASS), The Peer Interaction Paradigm (PIP)
Behavioural/emotional challenges	Child and Adolescent Symptom Inventory-4 ASD Anxiety scale (CASI-ANX), Child Behaviour Checklist (CBCL), Child Depression Inventory (CDI), Children in Stress (CiS), Depressioninventar fur Kinder- und Jugendliche (DIKJ), Emotion Quotient (EQ), Loneliness and Social Dissatisfaction Questionnaire (LSDQ), Paediatric Anxiety Rating Scale (PARS), Perceived Stress Scale (PSS), Revised UCLA Loneliness Scale, Social Interaction Anxiety Scale (SIAS), Strength and Difficulties Questionnaire (SDQ), The State Anxiety Inventory
Adaptive functioning	Adaptive Behaviour Assessment System II (ABAS), Developmental Disabilities Children’s Global Assessment (DD-CGASevaluating their efficacy is provided), OSU Autism Clinical Global Impression – Severity (CGI-S), Vineland Adaptive Behaviour Scale (VABS)
Autism characteristics	Asperger Syndrome Diagnostic Scale (ASDS), Autism Diagnostic Observation Schedule (ADOS), Social Communication Questionnaire (SCQ), Social Responsiveness Scale (SRS)