Evaluation of the Social ABCs in Israel

Feasibility will be assessed by tracking recruitment rates, retention throughout the 6-week program, and attendance at both group and individual coaching sessions. Acceptability will be evaluated through parent-reported satisfaction surveys completed at the end of the program, as well as qualitative feedback on the format, content, and delivery of the intervention.

The HCDI is the adapted Hebrew version of the MacArthur Communicative Development Inventory (MCDI). The MCDI is a well normed, reliable, and valid tool for vocabulary assessment (Bates et al., 1994). The HCDI is a reliable and sensitive measure of lexical development and emergent grammar, capturing wide variability among Israeli toddlers (Maital et al., 2000). We utilized two versions of the inventory: Words & Gestures for toddlers up to 25 months and Words & Sentences for children 25 months and older. This questionnaire relies on caregiver report to assess children's receptive and expressive vocabulary, speech comprehension, gesture use, morpheme acquisition, and syntactic complexity. In our study, we focused on two variables: receptive vocabulary total score and expressive vocabulary total score

The PSI-SR is a self-report, 36-item index of parenting-related stress. Each item is scored on a 5-point Likert-type scale, with higher scores indicating greater parenting stress (range 36-180). Alongside a total stress score, the three subscale scores are derived, each composed of 12 items (range 12-60): parental distress (PD), measuring distress caused by the burdens and restrictions of childcare and personal stressors (e.g., depression, conflict with partner); parent-child dysfunctional interaction (PCDI), assessing parents' negative perception of their interactions with the child and the degree to which the child does not meet their expectations; and difficult child (DC), measuring parents' views of the child's self-regulatory functioning. It also includes a defensive responding scale (DR; seven items, range 7-35), which assesses if the parent is trying to deny or minimize problems.

This is a semi-structured, standardized behavioral assessment of social communication abilities and restricted and repetitive behaviors. We used the ADOS-2 calibrated severity scores (CSS) to estimate autism symptom severity while separating CSS into the Social Affect (SA) and the Restricted and Repetitive Behavior (RRB) domains. The CSS were specifically developed to enable comparison of autism severity independent of the child's age and language abilities (Hus et al., 2014).

Verbal ability was evaluated using item A1 of the ADOS-2

The MSEL is a standardized developmental assessment that quantifies expressive and receptive language, motor, perceptual abilities, and motor development. All MSEL were administered and/or supervised by licensed developmental psychologists.

The ABAS-II Parent Form (ages 0-5) is a comprehensive norm-referenced parent-report rating scale used for measuring adaptive behaviors and skills in children on a 4-point Likert-type scale, with higher scores indicating better adaptive functioning. The ten skills of the ABAS-II are combined into a general adaptive behavior composite score (GAC) and three composites: conceptual (communication, functional pre-academics, and self-direction), social (social skills and leisure), and practical (self-care, home living, community use, health and safety).

The ABC is a caregiver-report measure of disruptive behaviors with 58 items, each rated on a four-point Likert-type scale (0-3), with higher scores indicative of more severe problematic behavior, on five subscales: Irritability (tantrums, aggression and self-injury, 15 items); Social Withdrawal (16 items); Stereotypic Behavior (7 items); Hyperactivity/Noncompliance (16 items); and Inappropriate Speech (4 items). In autistic children, the ABC subscales demonstrate adequate convergent validity (Kaat et al., 2014), however the scale does not have Israeli norms.

The CSBS-DP Infant-Toddler Checklist is a screening tool designed to determine whether a full developmental evaluation is warranted. It is a parent-report measure, consisting of 24 items that range from a possible of two to four points within each of seven clusters. Scores are given for three composites: Social Composite (Emotion, Eye Gaze, Communication and Gestures Clusters); Speech Composite (Sounds and Words Clusters); Symbolic Composite (Understanding and Object Use Clusters). Norms of the CSBS-DP are available only up to 24 months, so we used the raw scores

This is a 7-item questionnaire where parents reported whether the intervention was "helpful" in different domains. Ratings were completed using a 5-point scale (1: "not at all helpful" to 5: "extremely helpful").