Llemann, 2012; Lawton Kasari, 2012). Intervention sessions were based on developmental and behavioral principles consistent with JASPER. Parents were first taught to recognize the child’s current developmental level of play and use of social-communication gestures. Capitalizing on the child’s current level of play and interests, caregivers provided opportunities for the child to initiate interest in a toy/activity and to establish jointly engaged play routines. Parents used a number of strategies to keep children engaged while also improving their frequency of social communication gestures, spoken words, and play acts. Parents were taught to use these strategies in a structured sequence that has been previously tested (Kasari et al., 2010; 2014). Therapists, Supervision, and Treatment Integrity A post-doctoral clinical psychologist supervised all interventionists, and the majority of therapists were PhD candidates in Human Development and Psychology. Three of the eight different therapists were BA level therapists, all in the JASPER arm. Prior to beginning study treatments, therapists were required to demonstrate >90 fidelity on a PEI or JASPER-specific measure of fidelity with practice children, typically requiring 2 to 6 months of training. Supervision of active cases was conducted weekly. The project coordinator used a random numbers list to select sessions for fidelity ratings. To maintain blinding, the sessions were observed through a one-way observation window. Twenty Mangafodipir (trisodium) web percent of sessions were rated for treatment integrity with average ratings for PEI of 92.7 (78.6 ?00 ) and for JASPER, 91.4 (75 ?00 ). Measures Examiners blind to treatment status conducted all pre-treatment, post-treatment, and followup assessments. Separate video coders were also blind to treatment condition. The primary outcome was a measure of joint engagement coded from the Parent Child Interaction. A 10-minute interaction recorded between parent and child was collected pretreatment, post-treatment, and at the 6-month follow-up. Parents were asked to engage in free play with their toddler as they normally would at home using a standard set of toys (including dolls, dishes, puzzles, trucks, shape sorter, and blocks). Children’s joint engagement was coded using an adapted coding system from Adamson and colleagues (2009) where time jointly engaged included time in supported joint engagement and coordinated joint engagement, with or without symbols. Supported joint engagement was coded if the child demonstrated awareness of the parent’s participation (e.g., takes turns with the same object, follows parent suggestion in play with the object) while coordinated joint engagement was coded when the child directly acknowledged the partner through triadic eyeJ Consult Clin Psychol. Author manuscript; available in PMC 2016 June 01.Author Manuscript Author Manuscript Author Manuscript Author ManuscriptKasari et al.Pagegaze, language, and/or gesture. Instances of supported joint and coordinated joint engagement were coded as symbol infused if the child followed or showed evidence of attending to parent Mangafodipir (trisodium) site language or used language him/herself. For the purposes of this study, we combined supported joint and coordinated joint with and without symbols into a single variable of joint engagement consistent with previous studies (Kasari et al., 2010; 2014). Secondary outcomes from the parent-child interaction included child play skills, play level, and joint attention. The child.Llemann, 2012; Lawton Kasari, 2012). Intervention sessions were based on developmental and behavioral principles consistent with JASPER. Parents were first taught to recognize the child’s current developmental level of play and use of social-communication gestures. Capitalizing on the child’s current level of play and interests, caregivers provided opportunities for the child to initiate interest in a toy/activity and to establish jointly engaged play routines. Parents used a number of strategies to keep children engaged while also improving their frequency of social communication gestures, spoken words, and play acts. Parents were taught to use these strategies in a structured sequence that has been previously tested (Kasari et al., 2010; 2014). Therapists, Supervision, and Treatment Integrity A post-doctoral clinical psychologist supervised all interventionists, and the majority of therapists were PhD candidates in Human Development and Psychology. Three of the eight different therapists were BA level therapists, all in the JASPER arm. Prior to beginning study treatments, therapists were required to demonstrate >90 fidelity on a PEI or JASPER-specific measure of fidelity with practice children, typically requiring 2 to 6 months of training. Supervision of active cases was conducted weekly. The project coordinator used a random numbers list to select sessions for fidelity ratings. To maintain blinding, the sessions were observed through a one-way observation window. Twenty percent of sessions were rated for treatment integrity with average ratings for PEI of 92.7 (78.6 ?00 ) and for JASPER, 91.4 (75 ?00 ). Measures Examiners blind to treatment status conducted all pre-treatment, post-treatment, and followup assessments. Separate video coders were also blind to treatment condition. The primary outcome was a measure of joint engagement coded from the Parent Child Interaction. A 10-minute interaction recorded between parent and child was collected pretreatment, post-treatment, and at the 6-month follow-up. Parents were asked to engage in free play with their toddler as they normally would at home using a standard set of toys (including dolls, dishes, puzzles, trucks, shape sorter, and blocks). Children’s joint engagement was coded using an adapted coding system from Adamson and colleagues (2009) where time jointly engaged included time in supported joint engagement and coordinated joint engagement, with or without symbols. Supported joint engagement was coded if the child demonstrated awareness of the parent’s participation (e.g., takes turns with the same object, follows parent suggestion in play with the object) while coordinated joint engagement was coded when the child directly acknowledged the partner through triadic eyeJ Consult Clin Psychol. Author manuscript; available in PMC 2016 June 01.Author Manuscript Author Manuscript Author Manuscript Author ManuscriptKasari et al.Pagegaze, language, and/or gesture. Instances of supported joint and coordinated joint engagement were coded as symbol infused if the child followed or showed evidence of attending to parent language or used language him/herself. For the purposes of this study, we combined supported joint and coordinated joint with and without symbols into a single variable of joint engagement consistent with previous studies (Kasari et al., 2010; 2014). Secondary outcomes from the parent-child interaction included child play skills, play level, and joint attention. The child.