Table 2.

Effect direction plot for nature-based ECE vs. traditional ECE on social and emotional outcomes.

Study Author and Year	Study Design	Sample Size (E/C)	Study Quality	Social Skills ⊕	Social & Emotional Development ⊕	Attachment ⊕	Initiative ⊕	Fewer Behavioural Problems ⊕
Cordiano et al. (2019) [26]	Controlled before & after	12/14	Weak	▼	-	-	-	▼ (favours control)
Müller et al. (2017) [47]	Controlled before & after	43/45	Weak	▲	-	-	-	▼ (favours control)
Agostini et al. (2018) [59]	Controlled before & after	41/52	Weak	-	▲	-	-	-
Cooper (2018) [56]	Controlled before & after	13/11	Weak	-	▼	▼	▼	-
Ernst et al. (2019) [29,30]	Uncontrolled before & after	78	Weak	-	-	▲	▲	-
Fyfe-Johnson et al. (2019) [33]	Controlled cross-sectional	20/13	Weak	▲	▲	-	-	▲
Summary effect direction				▲	▲	▲▼	▲▼	▼ (favours control)

Abbreviations: E = experimental; C = comparison; ECE= Early childhood education. GRADE—(assesses the certainty of evidence at an outcome level): ⊕ = Very low. Effect direction: Study level: ▲ = positive association with nature-based ECE; ▼ = negative association with nature-based ECE. Controlled before & after studies—difference between experimental and control group at follow-up (unless stated). Uncontrolled before & after studies—change since baseline (unless stated). Controlled cross sectional—difference between experimental and control (unless stated). Cross-sectional—positive, negative or no association. Summary: ▲ = studies show a positive association with nature-based ECE; ▼ = studies show a negative association with nature-based ECE; ▲▼ = conflicting findings. Summary effect direction considers study quality, design (i.e., controlled before and after weighted more than cross-sectional) and sample size.