Trauma-informed Interventions in Early Childhood Education and Care Settings: A Scoping Review

Trauma in early childhood is a significant public health concern. Early Childhood Education and Care (ECEC) services are uniquely positioned to buffer the negative impact of early childhood trauma on children. This scoping review synthesized studies evaluating trauma-informed interventions in ECEC settings through a systematic search of four relevant online databases (PsycINFO, Medline, ERIC, A+ Education). Fourteen studies met the inclusion criteria, with 12 ECEC center-based trauma-informed interventions evaluated. Types and components of trauma-informed interventions, outcomes, and measures are presented. Findings suggest that trauma-informed interventions in ECEC settings are nascent but growing. Increasingly, programs are adopting multi-tiered system of support to address early childhood trauma, with these models suggesting promising results. The predominant focus of ECEC center-based trauma-informed interventions was upskilling teachers through training and coaching, with studies focused on assessment of teacher-level outcomes. Child, organization, and caregiver-level outcomes are not explored to the same extent, with evaluation of organizational outcomes relying predominately on qualitative methods. Whilst the short-term outcomes of trauma-informed approaches in ECEC have been examined, longer-term impacts and the causal mechanistic pathways of such programs have yet to be explored.


Trauma in Early Childhood
Early childhood is a critical developmental period that shapes children's long-term social, emotional, and physical health (Shonkoff & Phillips, 2000).Trauma at this sensitive period of child development is a significant public health concern that can have multiple detrimental impacts on children's development and health.Though no universally agreed terminology exists (Hanson et al., 2018), trauma, in this review, refers to an emotional response to a terrible event that leads to physical or psychological harm for an individual (American Psychological Association [APA], 2022).Childhood trauma encompasses childhood maltreatment by adults (e.g., neglect, abuse), traumatic experiences formally identified in DSM-5 criteria (APA, 2013), and adverse childhood experiences [ACE] (Feliti et al., 1998).These traumatic experiences can be either acute or chronic, directly experienced or witnessed, that overwhelm a child's ability to cope (Iachini et al., 2016).Extensive research evidence points to the deleterious consequences of childhood trauma for children, families, and society (e.g., Dye, 2018;Kempke et al., 2013).A secondary analysis of data from the Fragile Families and Child Wellbeing Study in United States found that 55% of preschool children had experienced one ACE and 12% had experienced more than three (Jimenez et al., 2016), while another indicated that 26% of children witness or experience a traumatic event before they turn four (Briggs-Gowan et al, 2010).The COVID-19 pandemic has resulted in increasing risk for childhood trauma (e.g., Cappa & Jijon, 2021).
Experiencing trauma without a supportive trauma-informed relationship and system in place may generate toxic stress, leading to intergenerational transmission of disparities in educational achievement and health outcomes, with potential consequence for the pathogenesis of adult disease (Shonkoff et al., 2012).Childhood trauma can harm children's neurodevelopment and functioning (e.g., brain, nervous system, endocrine system) (De Bellis & Zisk, 2014), social and emotional competence (Powers et al., 2015), behavior (Copeland et al., 2007), and executive functioning (De Prince et al., 2009).To buffer the potential negative effects of childhood trauma, a joint effort of services and support around the child (i.e., family, Early Childhood Education and Care (ECEC) centers, health providers) is needed.An increasing number of programs have been developed to respond to trauma-impacted young children's needs.However, an interdisciplinary review of trauma-informed practices over the past two decades suggests that researchers and practitioners are just beginning to engage with trauma-informed practices in educational settings (Thomas et al., 2019).

Trauma-Informed Approaches in ECEC
ECEC centers include long day care and childcare centers, kindergarten, nursery, preschool, and early learning centers where young children are cared for and educated by early childhood teachers (Organization for Economic Cooperation and Development [OECD], 2021).The term "teachers" is used throughout this article and refers to early childhood practitioners, with a breadth of qualifications and skillsets, who work with children in the ECEC environment.The Bioecological Model views child development as a complex system of relationships affected by multiple levels of the surrounding environment, from immediate settings of family and school to broad cultural values, laws, and customs (Bronfenbrenner & Ceci, 1994).Within this model, ECEC settings are situated within the microsystem, one of the most immediate environmental settings that play a vital role in child development.Factors such as the physical environment, teacher-child interactions, teacher beliefs and practices, policy and philosophy of centers are thus vital in responding to children who have been exposed to traumatic experiences.
Trauma-informed care, programs, systems, approaches, and environments are developed to mitigate the impact of trauma.An intervention is trauma-informed if it demonstrates a realisation of the widespread impact of trauma and understands potential pathways toward recovery; a recognition of the signs and symptoms of trauma in individuals and groups; a response that involves full integration of knowledge about trauma into policies, procedures, and practises; and efforts to prevent re-traumatisation of individuals and groups (Substance Abuse and Mental Health Services Administration [SAMHSA], 2014).Several multi-tiered frameworks have been developed to promote traumainformed care (e.g., multi-tiered system of supports, SAMHSA's (2014) Multi-tiered Model).In this review, we define Tier 1 as programs that upskill the ECEC workforce to benefit all children regardless of trauma experience (e.g., training and capacity building).Tier 2 includes targeted programs developed for children at risk of trauma or showing signs of related socio-emotional issues without formal screening (e.g., therapist-led play session delivered in the classroom for children who may have witnessed or experienced trauma).Tier 3 refers to individualized, intensive support for children with significant concerns (e.g., consultation for children with posttraumatic stress disorder by a psychologist; clinical therapy).A program is multi-tiered if more than one level of support is provided (SAMHSA, 2014).

Rationale for the Current Study
To our knowledge, previous reviews have not synthesized the evidence relating to trauma-informed interventions in ECEC settings in a comprehensive and systematic way.Recognizing the unique position of ECEC centers in responding to trauma-impacted young children and the paucity of such synthesis, a review focused on trauma-informed intervention in ECEC appears timely and warranted.
The aims of this systematic scoping review were to: (a) identify, describe, and examine the type of trauma-informed interventions that have been evaluated in ECEC settings; (b) examine child, teacher, classroom, and/or organizational outcomes that are associated with trauma-informed interventions in ECEC settings; (c) explore the measures that have been used to assess trauma-informed program outcomes; (d) explore the methodological limitations of research investigating the impact of trauma-informed programs applied in ECEC settings; and (e) make recommendations for policy, practices, and future research.

Method
The aim of this systematic scoping review was to explore the extent and scope of literature on trauma-informed intervention in ECEC.In contrast to a systematic literature review that seeks to answer specific and clearly defined research questions, a scoping review is suitable to determine the scope or coverage of a body of literature on a given topic, provide clear indication of the volume of literature available, and an overview of the research focus.A scoping review enables one to examine how research has been conducted, identify, and analyze knowledge gaps and informs practice in the field and future research (Munn et al., 2018).This review was conducted in accordance with the Preferred Reporting for Systematic Reviews and Meta-Analysis (PRISMA-ScR) guideline for scoping reviews (Tricco et al., 2018).

Search Strategy and Study Selection
Peer-reviewed papers in English were sourced from four relevant online databases: PsycINFO, Medline, ERIC, A+ Education.Publication dates were limited from 2011 to June 2022.Following SAMHSA's Concept of Trauma and Guidance for a Trauma-informed Approach (2014), there was increased use of trauma-informed approaches and programs within educational settings.Hence, the search window (2011-2022) is appropriate to comprehensively capture relevant, contemporary research.Three groups of key terms were combined to yield a comprehensive set of papers as shown in Supplemental Table S1.Covidence was used to manage the search results.Manual searching of references cited in selected papers and relevant reviews of school-based trauma-informed intervention programmes were undertaken, and suitable papers included.

Inclusion and Exclusion Criteria
Trauma-informed approaches have been increasingly embedded within ECEC programs.The search was limited to studies conducted in center-based ECEC settings, including kindergartens, preschools, and childcare services, for children from birth to age six.We recognize that center-based ECEC differs from home-based ECEC programs, such as family daycare, in several respects, including the environment and professional development available, which may influence trauma-informed intervention development, implementation, and evaluation.While it is important to understand the availability and effectiveness of trauma-informed intervention in non-center based ECEC settings, this was beyond the scope of the current review.The interventions of interest were those that explicitly targeted children who had experienced, were experiencing, or were at risk of experiencing trauma, or their early childhood teachers, or early years organizations who are preparing to be trauma-informed at a service level.Studies were included if they described a program that explicitly focused on the provision of traumainformed care or practices.Programs may target the teacher, child, classroom and/or organization, and at least one child, teacher, classroom, or organization-level outcome must be measured post-intervention.Study design was not restricted.For example, randomized controlled trials, quasi-experimental studies, pre-post designs, single subject designs, qualitative and mixed-methods studies were eligible for inclusion (for information please see Supplemental Table S2).

Review Procedure and Data Extraction
As shown in Figure 1, after removing the duplicates, 8,440 publications were evaluated at the title and abstract screening stage for potential inclusion against the criteria by two researchers [YS & CB].Any discrepancies in co-screening were resolved through discussion.A total of 121 papers were read-in-full to further assess the eligibility for inclusion, with 14 articles included in the review.The excluded studies focused predominantly on medical or dental trauma, and trauma-informed interventions in school settings.The following data were extracted from each study to allow comparison: (a) Study design (study aim, setting, theoretical framework, study design, location); (b) Characteristics of child and teacher participants (number, age, gender, ethnicity); (c) Intervention description (intervention name, format, frequency and duration, lead, caregiver involvement, fidelity); (d) Outcome measures, informant, and findings.
In order to classify each intervention as Tier 1, Tier 2, Tier 3, or multi-tiered, the following components of the intervention were extracted, informed by the SAMHSA's (2014) six principles and Avery et al.'s (2021) review of school-wide trauma-informed approaches: inclusion of staff PD (professional development/training), organization-level change (e.g., center-level capacity-building), cultural considerations/ adaptation, family involvement, inclusion of therapy, coaching, and explicit program delivery.

General Characteristics of Included Studies
Fourteen studies were included in the scoping review.The characteristics of each study are reported in Table 1.All were published between 2015 and 2022 inclusive and conducted in the United States.Seven studies reported quantitative data only [reference number in Table 1 : 2, 3, 5, 7, 11, 13, 14], with one study using a randomized controlled trial [3], two studies adopting a pre-test post-test control group design [5,7] and four studies using single-group pre-test post-test design [2,11,13,14].One study relied on qualitative methodology [1], and six adopted a mixed-method design [4,6,8,9,10,12].Among these, two studies adopted a single group pre-test post-test design [9,12], and one study each reported using a cluster randomized clinical trial [8], randomized controlled trial [10], controlled, pre-test post-test design [4], and feasibility evaluation using a mixed-methods approach [6].
Eleven studies [1-7, 9, 11, 13, 14] reported an underpinning theory or framework that informed the interventions.It is notable that five studies [2,4,5,7,14] reported the adoption of Attachment, Self Regulation, and Competency (ARC) Framework, which aims to support trauma-impacted children through strengthening the caregiving system, building capacity in self-regulation, and developing children's resilience (Blaustein & Kinniburgh, 2018)     adults surrounding the child (i.e., teachers, parents, administrators, bus drivers), provided by a master's level trained, licensed therapist.Children who may have witnessed traumatic events or experienced trauma were identified through behavior and trauma screening and referred to intensive trauma-specific supports (e.g., play therapy, sand tray).In addition, HSTS therapists provided classroom consultation for teachers and children on a need-basis, and teachers and supervisors were connected for peer-based mentoring.

Types of Trauma-Informed Interventions in ECEC
Except for the 2Gen Thrive program (Woods-Jaeger et al., 2018) that provided targeted classroom-based support for children and capacity-building sessions for parents at risk of toxic stress, all interventions included in-service training that aimed to promote teachers' awareness, knowledge, and skills relating to trauma-informed practice.In nine interventions [1-3, 5-7, 10-14], this professional development was coupled with coaching.For example, in Sunshine Circles (Tucker et al., 2017;2021), teachers participated in training and were then coached to deliver the intervention.
Five trauma-informed programs included an organizational component, with four classified as multi-tiered (Trauma supplement intervention [4]; TIC BSC Initiative [1]; TIES [5,7]; HNTC [12]).These typically involved training at an organization-level to promote a trauma-informed culture and coordinated implementation of trauma-informed practices.For instance, in the TIC BSC initiative [1], cross-role teams (i.e., teachers, administrators, leaders) were engaged to achieve a trauma-informed culture through distributed leadership from all levels of organizational system (Douglass et al., 2021). An
Child-level outcomes.Four studies found trauma-informed intervention in ECEC significantly and positively impacted children's behavioral outcomes [3,4,13,14].HSTS aimed to support social and cognitive development by creating an integrated, trauma-informed culture within Head Start centers.In Holmes et al. (2015), the Achenbach System of Empirically Based Assessment (Achenbach & Rescorla, 2000), a valid and reliable diagnostic tool, was used by teachers to assess children's behavior change, while the Child Behavior Checklist was completed by parents to evaluate children's behavioral outcomes after exposure to HSTS intervention.Both assessments were completed at time of referral, and either post-intervention or every 6 months, whichever arrived first.Teachers reported significant improvement in children's attention, externalizing Table 3. Key Findings of the Review.
• Trauma-informed intervention in ECEC settings is nascent but growing, with the predominant focus placed on training and coaching.
The inclusion of coaching in addition to training itself was suggested to increase fidelity and strengthen outcomes.• Increasingly, programs are adopting multi-tiered system of support to address early childhood trauma, with these models suggesting promising results.• Studies focused on assessment of teacher-level outcomes.Child, organization, and caregiver-level outcomes are not explored to the same extent, with evaluation of organizational outcomes relying predominately on qualitative methods.• While trauma-informed programs have led to positive outcomes for children, teachers, classrooms, and organizations, the sustainability of program impact is unknown, and the causal mechanistic pathways are yet to be explored.
behavior, and oppositional defiance.Similarly, parents reported significant improvement in externalizing problems, attention/hyperactivity, and internalizing behaviors in home settings.The Partnerships Program, which provided traumainformed workforce professional development, ongoing consultation, and trauma-specific interventions for identified children demonstrated similar benefits on children's behavioral development.Data collected at baseline and post-intervention suggested significant improvement in children's resilience (Shamblin et al., 2016).
Children's social-emotional competence was evaluated in three studies [3,9,10].Tucker et al. (2017Tucker et al. ( , 2021) ) examined the effect of Sunshine Circles on child development using two standard measurement tools.Data collected at three time-points during the year demonstrated significant improvements in children's social-emotional skills, behavioral regulation, problem-solving, and fine-motor control, in particular managing feelings, cooperation, accepting limits, peer-interaction, and friendship, and social problem-solving (Tucker et al., 2017(Tucker et al., , 2021)).Unlike Tucker et al.'s (2017Tucker et al.'s ( , 2021) ) adoption of standardized measures, Woods-Jaeger et al. ( 2019) conducted qualitative interviews with teachers to gauge children's social-emotional development post-intervention (2Gen Thrive).Benefits of Classroom Theraplay include greater expressiveness, increased interaction with peers and caregivers, and initiation of activities, where children showed enjoyment and ability to initiate connections with peers and caregivers (Woods-Jaeger et al., 2019).
Teacher-level outcomes.With the exception of 2Gen Thrive, all interventions included teacher training and teacher-level outcomes were the most commonly assessed outcomes.Teacher knowledge, attitudes, beliefs, and confidence were assessed in seven studies, with three qualitative studies adopting either an interview [1] or focus group [8], four quantitative studies utilizing a survey method [2,6,11,12], and one using direct observation of teacher practices [4].Among the three studies that used quantitative survey methods, three relied on scales that were developed for the study [2,6,11].The Attitudes Related to Trauma-informed Care measure [2] was the only psychometrically validated measure used.Teachers demonstrated increased understanding [1], awareness [1,2,11], knowledge [2,4,6,11,12], empathy [8], mindfulness [8], and skills [12] relating to traumainformed practice after participating in the intervention.
Five studies examined the impact of trauma-informed interventions on teacher behavior.Qualitative data collection methods included interviews with teachers and coaches [1], and focus group discussions [8], while quantitative studies relied on teacher self-report surveys [6,12], coach report [6], and observations [6, 10].Roots of Resilience [6], which involved online training and video-based coaching, was associated with significant improvement in teachers' language modeling and regard for child perspectives.Following the Sunshine Circles intervention [3,10], where teachers received training and coaching in an attachment-based program, teachers demonstrated increased ability to communicate with children, manage their classroom, and maintain a calm and active environment to support learning (Tucker et al., 2017).Similarly, qualitative findings showed teachers' increased use of trauma-informed strategies [1,8], familycentered communication skills [1], self-care strategies [8], communication strategies with children [10], and classroommanagement strategies [10] post-intervention.
Self-efficacy was evaluated in three studies [4,11,13].The Secondary Trauma Self-Efficacy Scale (Cieslak et al., 2013), a psychometrically evaluated, standardized measure, was used by Gilles and Carlson (2020) to evaluate a Trauma Supplement Intervention using a pre-post controlled design.Intervention and control groups did not differ with regards to teachers' self-efficacy following the intervention.However, in Shamblin et al. (2016), teachers reported significant improvement in confidence and hopefulness to impact challenging child behavior after taking part in The Partnerships Program, based on Teacher Opinion Scale (Geller & Lynch, 1999), a non-standardized, 12-item self-report measure.
Classroom-level outcomes.Two classroom-level outcomes were assessed in the included studies: teacher-child interaction quality and environment quality.The Classroom Assessment Scoring System (CLASS; Pianta et al., 2008) was used in six studies [4,5,7,9,11,14].This is a standardized, reliable, and valid observational instrument that assesses the quality of teacher-child relationships across three domains: Emotional Support, Classroom Organization, and Instructional Support (Pianta et al., 2008).Among the six studies employing this tool, two indicated a positive overall trend without providing specific statistics, following the 2Gen Thrive [9] and HSTS [14] programs.Of the remaining four studies, mixed results were reported.A significant increase in Emotional Support and Classroom Organization were identified in three studies [5,7,11]; however, inconsistent findings regarding Instructional Support were found, with two studies suggesting no significant differences between control and intervention groups (TIES) [5,7] at pre-and post-intervention (STRIVE) [11], and one reporting a significant increase in this domain [5].Interestingly, two studies that evaluated the same intervention (TIES) [5, 7] yielded different results.Rishel et al. (2019) [7] captured data from 52 classrooms and found no significant difference between intervention and control rooms in levels of Instructional Support.Tabone et al. (2020) [5] extended this evaluation using a stronger study design including matched classroom pairs and a larger sample (74 classrooms).They found significant improvement in rooms that participated in TIES compared to controls across all three CLASS domains (Tabone et al., 2020).
Only one study included a follow-up assessment.Whitaker et al. (2019) examined the ETA intervention using an online teacher survey including three outcome domains: relational capacities, health and wellbeing, relationship quality [8].The survey was completed by teachers at baseline, post-intervention, and 5-month follow-up.Results suggested that while the impact of ETA on conflict differed significantly by teacher education level at post-intervention, this difference was no longer significant at 5-month follow-up.No other significant changes in outcome measures were reported (Whitaker et al., 2016).
Organization-level outcomes.Organization-level outcomes were evaluated in two studies using qualitative methods [1,4].An amended version of the System of Care Traumainformed Agency Assessment (TIAA; THRIVE Evaluation Committee, 2011) was utilized for use in a Head Start preschool setting by Gilles and Carlson (2020).Six organizational-level elements were assessed: (a) physical and emotional safety, (b) trauma competence, (c) cultural competence, (d) commitment to trauma-informed philosophy, (e) trustworthiness, and (f) youth and family empowerment.Guided by the TIAA, Gilles and Carlson (2016) conducted structured interviews with informants including the director of preschool programs, Head Start Mental Health Consultants, site supervisors and teachers, both pre-and post-intervention, to explore organizational change.Findings suggested that administrators were more receptive to assessing and documenting children's trauma history in a uniform fashion, more aware of the impact of secondary trauma, and the necessity of providing support for staff (Gilles & Carlson, 2020).Increased trauma-awareness and readiness to change were identified within the ECEC center, with staff recognizing the benefits of trauma-informed practices and implementing TIC strategies at the organizational-level (Gilles & Carlson, 2020).Similarly, Douglass et al. (2021) examined the organizational practices and system change through indepth interviews, meeting observations, and reviewing documents such as improvement tracking forms and intranet posts, finding improvement in workplace relationships, shared leadership, collaborative learning, and interagency collaboration (Douglass et al., 2021).
Parent-level outcomes.Though parent-involvement was reported in five interventions, parent-level outcomes were only reported in one study.Training for parents to address intergenerational trauma was a significant component in the 2Gen Thrive [9] (Woods-Jaeger et al., 2018).A significant reduction in caregivers' depressive symptoms and distress, measured via standardized scales was identified between pre-to post-intervention.

Discussion
This review systematically examined the type of traumainformed programs that have been implemented and evaluated in ECEC settings, and explored the child, teacher, caregiver, classroom, and organization-level outcomes reported.The findings suggest that trauma-informed interventions in ECEC are nascent but growing, with the focus predominantly placed on teacher training and coaching.Training was delivered through in-person and online modules that aimed to promote teachers' awareness of trauma and its impact, support recognition of trauma-related behaviors, and provide strategies to support trauma-impacted young children.Eight interventions included both training and coaching.Coaching was delivered in-person in the ECEC setting, except for the Roots of Resilience program that relied on an online, relationship-based coaching model (Lipscomb et al., 2019).Results indicated both formats positively impacted teachers' knowledge and practice.Coaching strategies included modeling, guided practice with feedback, and reflection.The inclusion of coaching and/or consultation is more effective than training in isolation, as specialized coaching and consultation are responsive to teachers' needs and practices in context (Taylor et al., 2022).Coaching provides teachers with the opportunity to reflect on their practice and transfer knowledge and skills acquired through training into their practices.Combined coaching and training are likely to address challenges expressed by early childhood teachers relating to work with trauma-impacted children.For example, Lombardi (2020) claimed that teachers were overwhelmed by the quantity of strategies provided during trauma-related in-service training and faced difficulty incorporating learning into their practice.Hence, future interventions should also consider combining training and follow-up contextualized coaching to increase fidelity of the intervention and maximize effects.
Multi-tiered system of supports have not been adopted within ECEC to the same extent as other educational settings due to a variety of barriers (e.g., diverse types of early learning services with different funding sources; no universal curriculum) (Shepley & Grisham-Brown, 2019).The six trauma-informed interventions that were considered multitiered demonstrated promising impacts on child, teacher, classroom, and organization-level outcomes.In addition to universal Tier 1 level supports for all children (e.g., workforce training to create a supportive environment), targeted Tier 2 and/or individualized Tier 3 supports are also available in multi-tiered interventions.These holistic approaches have the potential to promote supportive early learning environments, assist teachers to identify child behaviors that may be related to traumatic experiences, and intervene early.
Among these multi-tiered programs, four included components that targeted organizational support and system change.However, only two examined organization-level outcomes, with evaluation relying on qualitative methods such as interview (Douglass et al., 2021;Gilles & Carlson, 2020).We suggest greater attention should be paid to trauma-informed organizational change in ECEC, where the infusion of trauma-informed awareness, culture, policies, and structures can support the teachers' trauma-informed practices and enable quality improvement (Douglass, 2016).Organizational change research also suggests that individuals face barriers adopting and sustaining new practices such as trauma-informed strategies without simultaneous actions at the broader system level (Douglass, 2016;Gittell, 2016;Kania et al., 2018).Psychometrically sound measures could support early learning organizations to better understand the extent to which they are trauma-informed, and monitor effectiveness of programming.Nevertheless, our findings are aligned with Champine et al.'s (2019) systematic review, that reported system-level measurement tools, especially related to the organizational environment and practices in educational contexts, were underdeveloped.
It is promising that cultural adaptations to meet the needs, values, and norms of the local community was considered in four programs.Such cultural adaptation is important and correlates with improved outcomes for ethnic and racial minorities (McMullen et al., 2013).In Kumpfer et al.'s (2002) evaluation of a culturally adapted version of the Strengthening Families Intervention, a 40% increase in program retention was reported.Finally, family involvement was described in five interventions.This included the provision of training materials to parents, with one program inviting parents to provide feedback on areas for improvement (Douglass et al., 2021).Though only one study evaluated parent-level outcomes, it reported a significant reduction in parental depression and distress (Woods-Jaeger et al., 2018).

Limitations of the Current Review
While this is the first review to synthesize the current evidence of trauma-informed interventions systematically and comprehensively in ECEC settings, several limitations should be considered when interpreting the findings.First, inclusion criteria were limited to studies published in English after 2011, thus relevant studies published in languages other than English and prior to 2011 may have been missed.The scoping nature of the review means that the quality of evidence captured was not evaluated.Further, social and emotional learning programs may include elements such as resilience that can buffer the negative impact of trauma (Sexton et al., 2015); however, these studies were not included as this review focused on programs where trauma was the explicit core focus.Given that all studies were conducted in the United States, caution should be applied when generalizing the findings to other cultural contexts, where ECEC service provision, teacher training, and inter-disciplinary support models may vary.

Limitations in the Evidence
Though examining the methodological quality of studies was not a focus of this scoping review, several methodological limitations in the studies emerged.First, studies tended to rely on self-report measures, leading to potential for response bias (Gilles & Carlson, 2020;Lipscomb et al., 2019;Tucker et al., 2017).The continued use of standardized measures will support a more robust and rigorous evidence-base.Second, evaluation of organization-level outcomes relied heavily on qualitative methods such as interviews (Douglass et al., 2021;Gilles & Carlson, 2020).Aligned with the finding of Champine et al.'s (2019) review and notwithstanding the deep insights that can be gleaned through qualitative research, we recognize the current gap in psychometrically sound measurement tools to assess trauma-informed systemlevel outcomes.Further, this review uncovered literature examining the effectiveness of ECEC trauma-informed interventions on short-term child, teacher, classroom, organization, and caregiver outcomes.However, little is known about the sustainability of such outcomes over time.

Future Directions
Despite limitations of current published evidence, findings of this review uncovered knowledge that could inform the development and improvement of ECEC trauma-informed interventions (See Table 4).The integration of coaching in addition to training appears to be effective in supporting teachers to translate what they have learned into their practice.There is also value in continuing to develop and evaluate multi-tiered trauma-informed interventions, and examine the sustainability of outcomes over time.Understanding of the context in which ECEC centers operate and the cultural and socioeconomic background of the children and families they serve can help tailor trauma-informed approaches (Cole et al., 2013).Finally, partnerships between families and their ECEC centers are critical to ensuring high-quality education and care (Cottle & Alexander, 2014).Partnering with families and caregivers, and listening to their perspectives should be further considered (Arthur et al., 2021).Such partnerships have the potential to inform and improve program implementation and enhance a trauma-informed culture within the community, and subsequently maximize child outcomes.

Conclusion
Trauma-informed intervention in ECEC settings is nascent but growing, with the predominant focus placed on training and coaching.The inclusion of coaching in addition to training itself was suggested to increase fidelity and strengthen outcomes.Increasingly, programs are adopting multi-tiered system of support to address early childhood trauma, with these models suggesting promising results.The majority of multi-tiered trauma-informed interventions embed a component that targets organization and system change.However, few evaluated organization-level outcomes, with researchers relying on qualitative methods to understand organizational impact.Further exploration of measurement tools and adoption of evaluation methods such as RCTs can enhance the evidence and potentially promote the application of traumainformed approaches in early childhood educational settings.While trauma-informed programs have led to positive outcomes for children, teachers, classrooms, and organizations, the sustainability of program impact is unknown, and the causal mechanistic pathways have not been explored.Longitudinal studies that explore program outcomes over time, and the causal mechanism that underline impact will advance our current understanding of the effectiveness of trauma-informed interventions in early childhood education and care settings.Monash University.Her background in developmental psychology, implementation science and prior to that, environmental science, has led to an interest in transdisciplinary research.Claire works across education, social care, and health to co-design, implement, and evaluate approaches that aim to strengthen children's development and positive mental health.Her current research focuses on early childhood social and emotional learning, teacher-child interactions, and trauma-informed practice.
Victoria Minson, PhD, is a Lecturer and Early Career Researcher at the Australian Catholic University's National School of Education.Victoria is interested in early childhood education pedagogy and practice, assessment, and cultural-historical theory.Victoria enjoys using theory and research to better understand practice-based problems.Helen Skouteris, PhD, is a developmental psychologist and the Monash Warwick Professor in Health and Social Care Improvement and Implementation Science.Her expertise and predominant research focus are on improving the health and wellbeing of mothers and children, working across health, community services, and education.

Rachael
Twelve trauma-informed interventions were captured, with three evaluated in two studies respectively (Traumainformed elementary schools [TIES] [5, 7], Trauma Smart [2, 14], Sunshine Circles [3, 10]).Detailed components of each intervention are shown in Table 2. Five programs were classified as Tier 1 (Sunshine Circles [3, 10]; Enhancing Trauma Awareness Course [ETA] [8]; Roots of Resilience [6]; Trauma Smart [2]; Supporting Trauma Interventions for Educators [STRIVE] [11]), as they focused on building the capacity of teachers, administrators, and organizations to benefit all children, without assessing children's experiences of trauma or providing further targeted and/or intensive support.One intervention was classified as Tier 2 (2Gen Thrive), developed in response to the high levels of early life trauma among parents and children within Head Start services (Woods-Jaeger et al., 2018).This program supported families at risk of toxic stress (i.e., high levels of ACEs), through Classroom Theraplay including therapist-led activities delivered to children in collaboration with teachers, and Dialectical Behavior Therapy Skills Training for Parents (DBT4P) consisting of psychologist-led group sessions aimed at improving parents' stress-management, and emotional regulation (Woods-Jaeger et al., 2018).This review did not identify any studies that evaluated a stand-alone Tier 3 intervention.However, Tier 3 intervention components were embedded in four multi-tiered interventions (Table 3).Six interventions (Head Start Trauma Smart [HSTS] [14]; Trauma Supplement Intervention [4]; Partnerships Program [13]; TIC BSC Initiative [1]; TIES [5, 7]; the New Haven Trauma Coalition [NHTC] [12]) were classified as multitiered because they involved more than universal workforce capacity-building, and incorporated at least one component focused on children in need of targeted support.For example, HSTS(Holmes et al., 2015) included training for all

Figure 1 .
Figure 1.Preferred reporting items for systematic reviews and meta-analyses chart.
trauma interventions for educators; ETA = Enhancing Trauma Awareness; HSTS = Head Start Trauma Smart; TIC BSC = The Breakthrough Series Collaborative; TIES = Trauma-informed elementary schools; NHTC = The New Haven Trauma Coalition.
Longitudinal methods are needed to better understand what works and what sustains with respect to trauma-informed intervention.This may also inform our understanding of how trauma-informed interventions affect children's learning and developmental trajectory over the longer term, and the return on investment for prevention and early intervention for children impacted by trauma within the ECEC sector.Finally, studies generally measured the effectiveness of interventions without exploring underlying causal mechanisms.How, why, for whom, and under what conditions interventions do or do not work is yet to be explored.Methodologies such as realist evaluation could help to uncover such knowledge (Pawson & Tilley, 1997).
Bajayo is the Manager of Impact and Evaluation at the Alannah & Madeline Foundation.Rachael has a Postgraduate Diploma in Health Promotion.With a background in public health, she works to address inequities-developing, monitoring and evaluating interventions for maximum social impact.Lee Cameron is the Head of Trauma Consulting at the Alannah & Madeline Foundation. Lee has a Bachelor of Social Science, and a Bachelor of Social Work.With a social work background, Lee has instigated many programs to help keep vulnerable children safe from the effects of violence.She currently oversees the Trauma Consultancy Service (TraCS) which helps educators working with children affected by trauma to understand the challenging behaviors being exhibited and how best to respond to them.TraCS facilitators are currently in 300 child care centers across Victoria.

Table 1 .
Study Characteristics.Not reported; ARC = The Attachment, Regulation and Competency; ECT = early childhood teacher; ECE = early childhood educator; TIC BSC = Trauma-Informed Care Breakthrough Series Collaborative; DBT4P = Dialectical Behavior Therapy Skills Training for Parents; CLASS = Classroom Assessment Scoring System; ECEC = Early childhood education and care; No. = study number.