This study uses a 3-year, prospective longitudinal (open) cohort design to compare (1) child development (physical, social-emotional, and cognitive) and children’s movement behaviors; (2) educator health and well-being; (3) educator job satisfaction and attitudes and beliefs toward outdoor play and learning; and (4) caregivers’ attitudes and beliefs toward outdoor play and learning between those at an outdoor-focused versus conventional full-day licensed ELCC program. We use a continuous recruitment approach (open cohort), whereby families and educators are invited to participate in the study leading up to either of the 2 annual data collection time points [22].

This study has received institutional research ethics board approval (#23/108X). Caregiver-child dyads and educators consent to 1 year of the study and are encouraged to reenroll for up to 2 years as long as the child remains at the center (refer to Figure 1 for study timeline).

Caregiver-child dyads are eligible to participate if children are between the ages of 10‐59 months at baseline, attend a participating ELCC center for 6 or more hours per day, 3 or more days per week, and if the caregiver can read, write, and understand English and/or French. Children with and those without disabilities will be eligible to participate in this study and efforts will be made to ensure study procedures and instruments fit the needs and abilities of children with disabilities. Educators are eligible if they are currently employed at a participating ELCC center, and they can read, write, and understand English and/or French. Participants are recruited from 2 types of ELCC programs: outdoor-focused (experimental) and conventional programs (usual care). The experimental and usual care programs are both governed by the same childcare organization and are licensed under the same provincial regulations. Given this, the centers are comparable in terms of cost per day, staffing ratios, and mealtime and nap protocols. The main difference between the centers lies in how the centers deliver the early years curriculum and where programming takes place. Details of the experimental and conventional centers’ programs, including setting, curriculum, and time outside, are detailed below.

The outdoor-focused ELCC center serves as the experimental group. This center prioritizes extended outdoor play and learning, with children spending the majority of the day outside year-round, regardless of the weather. The center is situated on 500 acres of forested land that children explore daily for learning and play. This expansive natural environment features a thick canopy of tall, established trees that provide significant shade, as well as a rich and diverse landscape with largely natural, grassy ground cover. Tree species are well mixed and include native varieties such as sugar maples, oaks, and several coniferous species. The terrain is varied, with exposed roots, rocky sections, and small but steep elevation changes, alongside wetlands and visible rock deposits that contribute to the site’s natural character and afford diverse sensory and physical experiences.

Each class has a designated “outdoor learning space” within the forested area. The infant group (<18 months) outdoor space is located closer to the building than those of the toddler (18‐30 months) and preschool (30‐71 months) groups; however, all classes have the flexibility to move beyond these areas depending on weather conditions and children’s emerging interests (Figure 2). Educators establish strong relationships with children on the land, setting clear boundaries that support safe supervision while still allowing for autonomy and exploration. The outdoor learning environments are intentionally designed to support inquiry-based and play-based learning. Natural and thoughtfully introduced provocations are embedded throughout the forest to spark curiosity and investigation. Features of the outdoor space include a fire circle, a sheltered eating area, picnic tables, climbing structures (eg, pallets and rope ladders), a secondary stick-built structure, and a rock wall that helps define boundaries. Daily experiences often include mud kitchen play, water and puddle exploration, gardening, and searching for insects and other small creatures (eg, salamanders, worms, and slugs). Natural materials such as sticks, rocks, and plants play a central role in children’s play and learning, supporting creativity, problem-solving, and physical engagement. The curriculum, while guided by the provincial early learning framework [22], emphasizes exploration, creativity, resilience, and environmental stewardship through immersive experiences in nature. Children are encouraged to engage with natural materials, ask questions, and observe ecological processes, such as plant growth and seasonal changes. Learning is child-led, play-based, and developmentally appropriate, with a strong emphasis on sensory experiences, movement, and connection to the natural world. Educators at the outdoor-focused ELCC typically hold specialized training, such as the Child and Nature Alliance of Canada’s Forest Practitioner certification or the Algonquin College Play, Learn and Teach Outdoors certificate. The educator team supports extended outdoor engagement through practices such as outdoor meals and snacks when feasible, as well as outdoor diapering routines for younger children. Indoor environments are used primarily for meals, rest, transitions, and as a safe refuge during extreme weather conditions (eg, excessive heat, severe cold, or thunderstorms).

Three conventional ELCC centers will serve as the usual care control group. These centers provide conventional programming with scheduled outdoor time typically meeting the regulated amount of outdoor time, a minimum of 2 hours a day (eg, 60 minutes, twice daily) in defined play areas (eg, playground, fenced-in grass, and fenced-in pavement or rubber spaces; Figure 3). Programming follows more structured routines with educator-led activities, guided by the same provincial early learning framework that the experimental site follows [23]. Physical environments include standard play materials and fixed playground equipment. The 3 conventional ELCC centers are located in different settings, one in an urban area inside an apartment building and is licensed for 49 children (10 infants, 15 toddlers, and 24 preschoolers). One is located in an urban area in the basement of a church and is licensed for 39 children (15 toddlers and 24 preschoolers), and one is in a suburban neighborhood attached to an elementary school and is licensed for 31 children (15 toddlers and 16 preschoolers); this site also has a kindergarten and school-age program. All locations (including the experimental location) are part of the Canada-wide ELCC program, which in Ontario in 2026 means that the childcare fee is capped at CAD $22.00 (US $15.50) per day.

A priori power analysis was conducted using G*Power (Heinrich-Heine-Universität Düsseldorf) to estimate the sample size required to detect meaningful group differences over time for the primary objective of the study (ie, child outcomes). Given the complexity of general linear mixed-effects models and the limited availability of accessible power calculation tools for these models, a repeated-measures ANOVA with a within-between interaction was used as an approximation. This approach allows for estimating power to detect changes within participants over 3 time points and differences between 2 groups (experimental vs usual care). The calculation assumed a small effect size (f=0.20), a power of 0.80, and an alpha level of .05. This choice aligns with findings from systematic reviews indicating that ELCC interventions often yield small but statistically significant effects on children’s development [24]. Based on these parameters, the estimated required sample size is 42 child participants (21 per group). While our primary analyses use general linear mixed-effects models, this conservative ANOVA-based estimate provides a reasonable benchmark for planning purposes and may underestimate statistical power. Given the open cohort design, in which participants may enter and exit over time and contribute varying numbers of observations, precise specification of variance and correlation parameters is challenging at the design stage. In the absence of prior data, assumptions were therefore based on conservative estimates. To further strengthen these estimates, an internal pilot approach will be used whereby preliminary data from the first year of the study (ie, Wave 1: T0, T1, and T2) will be used to estimate key parameters (eg, variance components and within-subject correlation). These estimates will inform a refined assessment of sample size and statistical power for the remaining study period. This process will not involve formal hypothesis testing and will not affect the integrity of the primary analyses. The current sample size estimation is treated as a minimum threshold. In practice, we aim to enroll 100% of children attending the outdoor-focused ELCC center (ie, experimental site) and seek to match this number across the usual care sites. Therefore, we anticipate a substantially larger sample size that will improve the precision and generalizability of our findings [25].

Data are collected by trained assessors following detailed standard operating procedures to ensure consistency across assessments. At the same time, a universal design approach [26] is taken to promote inclusion and accessibility for all children. For participants with identified disabilities, a member of the study team experienced in working with children with disabilities will consult with the classroom educator and the study team’s resource consultant in advance of the assessment to plan any necessary adaptations. While standardized procedures are followed whenever possible, assessments that a child does not have the ability to complete are not administered. In some cases, tasks may be modified to better align with a child’s abilities (eg, permitting use of a mobility aid when demonstrating a kicking task). All deviations from standard procedures are documented, and sensitivity analyses will be conducted to examine the impact of including or excluding children who did not complete the full standardized protocol on the study results.

Assessments with children take place on-site during ELCC hours 3 times per year: baseline (T0), 6-month follow-up (T1), and 12-month follow-up (T2). For children who reenroll in the study after 1 year, assessments will continue every 6 months for up to a total of 6 follow-up assessments. There will be 3 waves of data collection representing 3 cohort groups across 3 years (Figure 3). Important to note, “waves” are distinct from time points; time points (eg, T0 and T1) refer to when data are collected during the study, whereas waves refer to when groups of participants are enrolled in the study. Testing of all children is typically completed over a 1-month period in the summer (August) and winter (February). To support children’s understanding of the research activities and to promote their engagement, a Research Garden (Figure 4) was created at the experimental ELCC program. This space offers a welcoming, familiar environment where children can explore materials, ask questions, and participate in tasks more comfortably. By embedding the research within an inviting, playful setting, the Research Garden helps motivate children, reduce apprehension, and foster a sense of curiosity and involvement in the study. Although we were unable to establish a Research Garden at usual care sites, we support children’s engagement through regular visits to the center to build familiarity with the research team. We also worked with the educators to select a temporary, quiet, child-friendly space for assessments and will use the same space for future assessments to build comfort. We also use engaging materials (eg, a teddy bear wearing an accelerometer) and small incentives (eg, stickers) to promote participation.

Caregiver questionnaires are distributed via REDCap, a secure, institutional web-based data management platform, following each assessment and are completed within 7 days of the assessment date. Each child is assigned a unique study ID and added to a password-protected master list to securely track data across all time points. During each assessment, children complete a battery of standardized assessments appropriate to their age group and ability (details provided below). Data are recorded on hard-copy data collection forms and then entered into REDCap following the assessment. One research staff member enters the data, and another verifies it for accuracy.

Educator questionnaires are distributed following the same schedule as child assessments. Educators receive a REDCap questionnaire 3 times per year and are asked to complete the questionnaire electronically within 7 days of receiving it. Educators are also invited to reenroll in the study for up to 3 years (or a maximum of 6 follow-up questionnaires).

The objectives of this study will be assessed using a combination of direct child assessments and caregiver and educator questionnaires. These instruments are described in detail in the following section. A summary of measures for children, caregivers, and educators can be found in Table 1.

Each component of the educator questionnaire is briefly described below; for full details, refer to Multimedia Appendix 2.

As part of the SPROUT study, a substudy titled “SPROUT-able” is being conducted to assess social and built environmental barriers and facilitators to outdoor play and learning in natural spaces of the outdoor-focused ELCC program (experimental site) for children with disabilities and/or identified challenges in one or more functional domains (ie, seeing, hearing, walking, fine motor, communication, learning, and playing, behavior) [55].

To support meaningful community engagement in the SPROUT-able substudy, we formed a collaborative group of community partners and individuals invested in improving outdoor play opportunities for children with disabilities who have professional and/or lived experience with disability (which includes the children they work with, their own children, or themselves). These partners contribute lived and professional expertise to guide the substudy’s design and implementation. To clarify roles and support shared decision-making, we use the Involvement Matrix (Multimedia Appendix 4) [56]. The Involvement Matrix is a tool used in partner-engaged research to clarify and visualize the different roles and levels of participation that partners or stakeholders can take throughout the various phases of a research project. This approach promotes transparency, supports reciprocal learning, and ensures the research remains responsive to community priorities.

To identify children with a disability or who may potentially have a disability, we will use a combination of caregiver-reported diagnosis, a validated caregiver questionnaire of functional abilities, and reports from the inclusion support worker. As part of the SPROUT study caregiver questionnaire described previously, caregivers are asked whether their child has been diagnosed with a disability (yes, no, in the process of getting a diagnosis), and if yes, to provide a brief description. Recognizing that many disabilities go undiagnosed in early childhood [55], we have implemented 2 other processes for identifying children who may have additional challenges in one or more developmental domains that could impact their participation in outdoor play. First, all caregivers complete the Washington Group/UNICEF Child Functioning Modules - Ages 2‐4 Years [55]. This tool is designed to capture challenges a child experiences in daily functioning. Aligned with the International Classification of Functioning conceptual model of disability [57], this tool focuses on what children can do and the level of difficulty they experience, rather than on medical diagnoses. Questions cover 8 functional domains (ie, seeing, hearing, walking, fine motor, communication, learning, playing, and controlling behavior) with response options that capture different levels of difficulty to reflect the severity of a child’s functioning (eg, no difficulty, some difficulty, a lot of difficulty, and cannot do at all). For the purpose of the SPROUT-able study, children are identified as potentially having a disability if the caregiver indicates “a lot of difficulty” or “cannot do at all” in one or more functional domains, consistent with the Washington Group/UNICEF guidelines. Where appropriate, we will further categorize children by severity level (eg, low to high functional difficulty). Finally, the inclusion support worker, who works in collaboration with the study team and the ELCC center, will document which children require ongoing additional support in the classroom, indicating a potential disability or developmental challenge. The inclusion disability support worker will do this by completing a checklist that aligns with the Washington Group/UNICEF guidelines used in the caregiver questionnaire. Disability status is reassessed every 6 months, given the rapid developmental changes in early childhood and the evolving demands placed on children as they grow.

Descriptive statistics are used to summarize participant characteristics and all primary measures, including developmental assessments, movement behaviors, caregiver attitudes, support behaviors, and educator outcomes. Means and SDs are reported for continuous variables, and frequencies and percentages for categorical variables. General linear mixed-effects models will be used for the primary objective and secondary objectives 1 and 2 to examine differences in change over time and between groups. Separate models will be specified for child developmental outcomes (eg, motor, cognitive, and social-emotional), movement behaviors (eg, physical activity, sedentary time, and sleep), caregiver attitude and support measures, and educator-reported measures (eg, job satisfaction, health and well-being, and attitudes toward outdoor play). Models will include fixed effects for time (eg, T0 and T1), group (experimental vs usual care), and relevant covariates (eg, child age, sex, disability status, race and ethnicity, parent income, parent education, and newcomer status). For covariates with small subgroup sizes, distributions will be examined prior to modeling; where sparse categories are identified, categories will be collapsed as appropriate to ensure stable estimation. A random effect for participant (study ID) will be included to account for within-subject correlations across time points. The primary analyses will treat the 3 usual care sites as a single group. Sensitivity analyses will additionally adjust for the ELCC site (included as a fixed effect) to examine potential differences between individual usual care centers and to evaluate the extent to which such differences may influence the results.

Interaction terms (eg, group × time) are tested to examine whether changes over time differ between the experimental and usual care group, thereby estimating intervention effects as differences in change from baseline. Because baseline measurements are included as part of the repeated outcome in the mixed-effects models, this approach inherently adjusts for baseline differences between groups. The mixed-effects models accommodate unbalanced data, such that participants are not required to have observations at all time points; individuals with missing baseline or follow-up measurements contribute all available data to the analysis. These missing time points are handled within the maximum likelihood framework under a missing at random assumption, avoiding listwise deletion. Missing data within completed measurement occasions (eg, partial or item-level missingness) will be explored and, where appropriate, addressed using additional methods (eg, multiple imputation) based on the nature and extent of missingness. Model assumptions are checked using residual diagnostics. Statistical significance is set at less than P=.05. Effect sizes are computed and interpreted using established guidelines, with CIs reported to aid interpretation of both statistical and practical significance. Interim analyses are conducted after each year of the study and final analyses will be conducted after all data collection is complete (Figure 1). All analyses are conducted in R version 4.4.2 [28] using RStudio version 2024.12.0+467 [29].

The SPROUT study is the first in Canada, and to our knowledge globally, to directly and longitudinally compare a licensed outdoor-focused ELCC program with conventional ELCC programs. This research addresses a significant gap in the current evidence base regarding the short- and long-term developmental and health impacts of outdoor-focused ELCC models. By using a robust and appropriately powered design, the SPROUT study provides a unique opportunity to examine whether and how outdoor-focused ELCC models influence not only child health, development, and well-being, but also caregiver beliefs and attitudes, and the well-being, job satisfaction, and continued professional development of educators.

Importantly, the SPROUT study explores how outdoor-focused programs affect educators’ knowledge and attitudes toward outdoor play. These insights may support strategies to retain and strengthen the early childhood education workforce, a major challenge and need in Canada, given the new Canada-wide Early Learning and Child Care Act, which commits to adding 250,000 new licensed ELCC spaces in Canada by March 2026 [64]. The study also examines caregiver attitudes and support behaviors toward outdoor play, offering valuable information on how these beliefs evolve over time and differ across program types. This knowledge will serve to expand on the growing body of work being done in Canada exploring caregiver and educator perspectives of outdoor play and learning and how to support change toward promoting more outdoor play opportunities for all children [11,65]. Together, this body of literature may help inform strategies to promote outdoor play in ELCC, at home, and in community spaces.

The SPROUT study and the SPROUT-able substudy place a strong emphasis on inclusion by intentionally examining outcomes among children with disabilities. Children with disabilities are frequently excluded from ELCC settings or experience marginalization while enrolled [66]. Exclusion especially occurs during outdoor play, where both physical and social barriers are common [13-16]. By investigating how outdoor and nature-focused programs can foster environments that support the full participation of children with and those without disabilities, this study will provide insight into how outdoor play can potentially be used as a strategy to promote inclusion. In addition, by intentionally including children with disabilities, this study will be able to glean insight into the potential benefits of outdoor play and learning on child health and development for children with disabilities, an area of research recently identified as requiring more robust experimental evidence [67]. With these findings, there may be an opportunity to inform not only licensed ELCC practices but also broader community-based outdoor play initiatives and early years programs aimed at reducing barriers and increasing access to play outdoors and in nature for children with disabilities.

This study has several notable strengths. The longitudinal cohort design enables temporal comparisons between outdoor-focused and conventional ELCC programs, providing insight into developmental changes over time. The study is appropriately powered, and the use of a naturalistic cohort design adds rigor and ecological validity. A comprehensive set of valid and reliable child outcome assessments, including both direct measures and caregiver-reported tools, ensures robust data collection. Additionally, this study examines changes in educator well-being, an area that has received little attention in outdoor-focused ELCC programs.

Despite this study’s strengths, there are limitations that we anticipate having a potential impact on the findings. Due to the naturalistic design of this study, randomization is not possible, which may influence causal inferences. Families self-enroll in the outdoor-focused program, introducing the potential for selection bias. However, both the experimental and usual care sites are funded through the Canada-wide Early Learning and Childcare program, where caregivers put their name on a city-wide waitlist and typically accept whatever program has capacity. Similarly, educators also self-select and apply to work at the center of their choice, and the outdoor-focused ELCC prioritizes educators who have training in outdoor-focused childcare, introducing a possible selection bias. To address this, we will explore baseline differences and focus our analyses on differences in change over time, inherently accounting for individual differences. Accessibility is also limited, as the outdoor-focused center is located outside the city center and is not yet reachable by public transit, potentially leading to a less diverse sample. Selection bias is likely, as families participating in the SPROUT and/or SPROUT-able studies may have an interest in child development, movement behaviors, and/or outdoor play, which could influence study outcomes. Finally, while a strength of this study is the intentional inclusion of children with disabilities, the study remains limited by a lack of valid and reliable measures of child development and health for diverse disability types.

By taking a holistic and comparative approach that includes children with and those without disabilities, caregivers, and educators, the SPROUT and SPROUT-able studies offer comprehensive evidence to inform early childhood research and ELCC practice and policy in Canada and internationally. As countries look for sustainable, inclusive, and evidence-informed system approaches to early learning and development, this study provides a timely and evidence-based Canadian model that can guide efforts to better integrate inclusive outdoor play into early learning systems. Ultimately, this study has the potential to drive meaningful and inclusive improvements in ELCC settings by demonstrating if and how outdoor-focused programs can promote child development and healthier communities.