Opt In - Implementation and Evaluation of an Early Intervention Program for Children Waiting to Receive an Autism Diagnosis - Parent-mediated early interventions for autism during toddlerhood are beneficial; however, intensive, autism- specific interventions typically do not begin until a child receives a diagnosis. As the median age of diagnosis in the US is 49 months, and services often do not begin for another 9 months post-diagnosis on average, this creates harmful delays. Such delays in accessing autism-specific early interventions are potentially avoidable, as caregivers of children later diagnosed with autism often identify concerns about their child’s development by 13 months on average– including difficulties that can be successfully addressed through evidence-based intervention practices. Wait times to receive a formal diagnosis of autism are such a significant barrier that they have been referred to as a “crisis” in the field, with parents reporting an average wait time of 1.2 years in the US and even longer in Canada. The current proposal focuses on circumventing the roadblock of delayed access to diagnosis and intervention by empowering caregivers to address their children’s needs before a diagnosis is established. This will be accomplished through the implementation and evaluation of the “Online Parent Training in Early Behavioral Intervention (OPT-In-Early)”, an online resource for caregivers of autistic children which will be made available to caregivers who are awaiting a diagnostic evaluation for their child. The Opt-In-Early program includes modules designed for self-directed implementation and individualization based on caregiver priorities, as well as access to remote consultation with a clinician for advice, clarification and support. Following an alternative approach to the current “parental concerns – then enrolment in waitlist – then clinical diagnosis – then intervention”, the proposed program is designed to counteract the harmful and frustrating inaction that characterizes the waiting period with timely action designed to address areas of concerns that caregivers have already identified and should be empowered to address. The evaluation of this innovative program will be achieved by comparing outcomes for 120 children aged 16-48 months who are on a waitlist to receive a formal autism diagnosis, randomly assigned to receive either OPT-In-Early or to a waitlist condition for 6 months. Examining whether accessing and using OPT-In-Early during waitlist time is a viable alternative to the current “first diagnosis then intervention” format can be a critical step toward promoting a more efficient intervention delivery model, bridging the gap between timing of parental concerns and availability of interventions designed to target such concerns. Therefore, in the context of the current waitlist crisis and chronic shortage of trained professionals in the areas of autism diagnosis and intervention, the proposed project has the potential for a high impact in the field. Additionally, given the alignment of OPT-In-Early with other evidence-based interventions, the relevance of this research question extends beyond the intervention under examination.