In The Lancet's series on advancing early childhood development, provision of high-quality early childhood care and education was listed as one of the main factors that can maximize children's potential to succeed in later life, particularly children from vulnerable or disadvantaged backgrounds. High-quality early childhood care and education is widely understood to be important for equipping children with essential skills and competencies across academic and non-academic areas, which in turn increases school readiness and has long-reaching impacts on outcomes later in life. Despite the government's efforts to support the early childhood sector, educators in Singapore continue to report difficulties in implementing practices in classrooms that promote children's social, emotional and cognitive development. To enhance educators' skills in these domains, we developed the Enhancing and Supporting Early development to better children's Lives (EASEL) Approach, a set of universal educator-led practices for use with 3-6-year-old children to improve social, emotional, behavioral and executive functioning (SEB+EF) outcomes. This study will evaluate the implementation and effectiveness of the EASEL Approach on improving early childhood educators' teaching practices and in turn, children's SEB+EF outcomes. We will conduct a type 2 hybrid implementation-effectiveness design in a cluster randomized controlled trial in 10-12 childcare centers. We will use the EPIS (Explore, Prepare, Implement, Sustain) Framework to support the implementation of the EASEL Approach. Implementation strategies include training, educator self-assessments, practice-based coaching, and data monitoring. Primary outcomes include educator's teaching practices and their adoption of the EASEL Approach in everyday practice. Secondary outcomes include the acceptability and feasibility of the EASEL Approach and children's SEB+EF outcomes. Quantitative and qualitative data will be collected at baseline, three months and six months.

The specific aims of the EASEL trial are two-fold:

1. The first aim is to test the effectiveness of the EASEL Approach, a universal classroom-based approach (evidence-based classroom practices identified using a common elements approach) on enhancing educators' classroom practices to improve SEB+EF outcomes in preschool children. We hypothesize that the EASEL Approach will improve educators' teaching practices related to promoting preschool children's SEB+EF outcomes. In turn, improvements in children's outcomes in these domains in the longer term (e.g., six months) will also be observed.
2. The second aim of the trial is to understand how educators implement the EASEL Approach within their classroom and the factors that affect the implementation. We hypothesize that with the use of the implementation strategies proposed for the trial (educator training, educator self-assessment of intention to use and self-efficacy, practice-based coaching, and data monitoring), the EASEL Approach will be well adopted by educators, implemented sustainably and achieve its desired effects.

The EASEL trial is based on three key studies.

• The Growing Up in Singapore Towards healthy Outcomes (GUSTO) Study: A longitudinal birth cohort study of maternal and child health indicating significant relationships between conditions during pregnancy and early childhood on later outcomes of physical, mental and social well-being.
• McLeod et al. (2017): This trial builds on the systematic review to identify common elements considered for inclusion as part of the EASEL Approach.
• Work conducted by Assistant Professor Evelyn Law and colleagues at NUS Yong Loo Lin School of Medicine: The Whole Child Panel (WCP) 2.1 will be used in the EASEL trial as a screening measure of children's executive functioning and the Executive Function Playbook will be included as one of the EASEL practices.

The EASEL trial will employ a Type 2 hybrid implementation-effectiveness design using a cluster randomized controlled trial. A hybrid design approach involves the simultaneous evaluation of both a programme's outcomes as well as the effectiveness of the implementation of the programme. A Type 2 hybrid design also enables the assessment of the feasibility of the programme.

As part of the trial, 12 childcare centres will be randomized to receive training in the EASEL Approach (six sites, referred to as the intervention sites) or continue with business-as-usual (BAU) (six sites). Educators in the BAU group will be provided the option to be trained in the EASEL Approach following completion of the study.

The EASEL trial will be guided by the EPIS (Explore, Prepare, Implement, Sustain) Framework, an evidence-informed framework frequently used in programme implementation and evaluation. The EPIS Framework considers the multilevel nature of service systems (e.g., the early childhood sector in Singapore), the organizations within systems (e.g., individual preschool operators in Singapore), and the 'client' needs (e.g., the needs of children and early childhood educators) when implementing a new programme. It highlights four key phases that guide and describe the implementation process: Exploration, Preparation, Implementation, Sustainment. The Exploration phase involves identifying the problem, developing appropriate and evidence-based solutions, and considering factors that might impact implementation. In this context, the problem is the gap in educators' skills to enhance children's SEB+EF development, and the solution is the EASEL Approach. The Preparation phase consists of a planning process with key stakeholders (e.g., relevant government agencies, preschool operators, individual childcare centers) for the implementation of the new programme. When sufficient preparation has occurred, the Implementation phase commences (implementation of the EASEL Approach by educators in their classrooms). Factors affecting implementation include outer and inner contextual issues (e.g., resource availability, fit with educators' current practices, organizational culture, and attitudes) and consumer concerns (e.g., the applicability of practices for educators' and children's needs). When the new practices have been routinely used, the Sustainment phase can begin. This involves the sustainment of the new programme in the current setting and may also include scaling-up to other settings and systems.

Inclusion Criteria:

For childcare centres:

• The childcare centre provides full-day programming for children at the Nursery 2 (N2), Kindergarten 1 (K1), and Kindergarten 2 (K2) levels (i.e., children between 3-5 years old at the start of the school year).Childcare centre has one of each class level that can participate in the EASEL trial (e.g., one N2, one K1 and one K2 class in each childcare centre).
• Childcare centre is not currently implementing other substantial SEB/EF programmes or involved in other trials evaluating SEB/EF programmes

For early childhood educators (adults):

• Both L1 and L2 educators will be eligible to take part in the trial. Inclusion of educators with a variety of experience will allow the research team to understand the effectiveness of various implementation strategies for each group. L1 educators are certified by the Early Childhood Development Agency (ECDA: government regulatory body for early childhood education) for deployment at nursery, pre-nursery and playgroup (i.e., children aged 18 months-4 years old) and L2 educators are certified by ECDA for deployment at kindergarten, nursery, pre-nursery and playgroup (i.e., children aged 18 months-6 years old).
• Educators must be ECDA-certified English-language educators.

For children:

• Children must be enrolled in N2, K1 or K2 classes at the start of the trial.
• Child is attending the participating childcare centre, in the selected class.
• Child is enrolled to attend a full-day childcare programme.

For parents/caregivers:

• Parent/caregiver needs to be the primary caregiver of the target child in the study.
• Parent/caregiver needs to be able to read/write in English. Where parents/caregivers are not proficient in English, their consent will be sought with the aid of interpreters, but data will only be collected for their child via teacher reports.

Exclusion Criteria:

For childcare centres:

• Childcare centre does not have at least 1 class at each age level (N2, K1 and K2 level).
• Childcare centre is currently implementing other substantial SEB/EF programmes or involved in other trials evaluating SEB/EF programmes.
• Childcare centre is currently involved in other research trials.
• Childcare centre currently has areas of concerns flagged to ECDA for review.

For early childhood educators (adults):

• Educator does not have either L1 or L2 certification
• Educator does not teach primarily in English.

For children:

• Child attends only a half-day or flexi childcare programme.

The centers will be randomized by the research team to the intervention group (five to six centers) or control group (five to six centers) using a random number generator.