Curriculum-linked learning outside the classroom (field trips, museum visits, outdoor teaching) raises school achievement compared with teaching the same content only in the classroom, by about 0.3 standard deviations in randomised studies (about 0.5 across all studies, inflated by non-randomised ones), and more in primary school than later.
Status
weakened
Last change
2026-11-08
Serves
Q1 (How do humans actually learn, and what helps them learn best?)
Ages
grundskola-lag, grundskola-hog, gymnasium
Area
Learning outside school
Relates to
C27 relates-to C28 (both about learning outside the lesson)
Bounds
Structured, curriculum-linked activities outside the classroom; not homework (C27) and not unstructured leisure. Evidence on file: Delen et al. 2026 (Sustainability 18(3), 1437, DOI 10.3390/su18031437; full text read 2026-11-08, open access): 42 studies (1970–2022), 54 effect sizes; overall g = 0.529 (95% CI 0.392 to 0.665; Q = 744.8, df 53); by design (Table 3), randomised studies g = 0.307 (0.167 to 0.447, k = 29) vs non-randomised g = 1.020 (0.722 to 1.318, k = 16), and the authors say stronger claims should rest mainly on randomised or well-controlled studies; by region, North America g = 0.149 (−0.010 to 0.308, k = 15) and Scandinavia g = 0.180 (−0.093 to 0.454, k = 4), against Türkiye 1.023 (k = 11); by subject, science 0.632, social science 0.757, maths 0.295, reading 0.166; by level, elementary 0.805, middle 0.617, secondary 0.500 (grade slope −0.136, p = .002; subgroups not adjusted for design); exposures of 2–6 hours g = 0.034 (−0.163 to 0.230, k = 7). The meta-analysis does not code or report test delay, so durability is not addressed; its assessment-item-type figures differ between Table 3 and the text. Holmes 2011 (Learning Environments Research, DOI 10.1007/s10984-011-9094-y; abstract only): 228 grade-6 pupils randomly assigned to control, museum exhibit, lesson or both; the exhibit group gained, but no lasting differences between groups were shown — a warning on durability. A bold claim: the size rests on one meta-analysis, now read in full; the half-SD average is not the randomised estimate. Regular weekly outdoor teaching (udeskole-type), full text of Becker et al. 2017 (IJERPH 14(5) 485, DOI 10.3390/ijerph14050485; §3, Tables 1–3): a systematic review of 13 studies found no randomised trial, one controlled study with standardised tests (a one-year out-of-school science programme for fifth graders; reading and writing higher than controls, p = 0.03, no effect size given, maths not reported) and no delayed achievement tests.
What would kill this
A meta-analysis or large randomised trial finds that curriculum-linked out-of-school learning does not raise achievement over classroom teaching of the same content, or that the gain is gone on a delayed test. Promoted from K58 on 2026-10-29 in the bold expansion Jonatan approved after four empty attack nights (26–29 Oct): new sharp claims in thin areas, each naming a comparison, a rough size or direction and a population.
Tutor consequence
none yet
Attack record
1 attack: 1 narrowed
2026-11-08 narrowed
Attack
The full text of Delen et al. 2026, the only source for C28's "about half a standard deviation", shows that the half-SD average is carried by non-randomised studies: randomised studies give g = 0.307 (95% CI 0.167 to 0.447, k = 29) against g = 1.020 for non-randomised ones (k = 16), and studies from North America (0.149, CI −0.010 to 0.308) and Scandinavia (0.180, CI −0.093 to 0.454) do not clearly differ from zero.
Target
claim-text
Source
Delen, Özüdoğru, Şen & Biasutti 2026 | Sustainability 18(3), 1437, DOI 10.3390/su18031437 (open access, CC BY; full text read on the publisher's article page, Tables 2–4)
Steelmans to
C28 states the size as "about half a standard deviation on average", but the authors themselves say stronger claims should rely mainly on randomised or well-controlled studies, and in their own Table 3 the randomised estimate is about 0.3; the half-SD figure is the pooled value across designs (Q_B = 17.998, p < 0.001 for the design split).
Why
Nightly-attacks 2026-11-08 Europe/Stockholm. Delen et al. had been on file as abstract only; the publisher page opened tonight and the full text was read. Not a restatement of the existing Bounds ("high heterogeneity; depends on how well the activity is tied to teaching" did not split by design or region) and not a duplicate of the 2026-11-02 Becker correction. "More in primary school than later" holds in the full text (elementary 0.805, middle 0.617, secondary 0.500; grade slope −0.136, p = .002), though those subgroups are not adjusted for design. Not a preprint. Claim stays under ~600 characters, so no rewrite to shorten the claim was needed. Status alive → weakened.
Rewrite
claim-field+brief
Corrections to our notes
These fix a number or a fact in our notes. They are not attacks and do not count toward the floor of 3 survivals.
— C28's limits do not record what the full text of Becker et al. 2017 shows for regular weekly outdoor teaching: no randomised trial, one controlled standardised-test study, no delayed achievement tests (a closer reading of the study).
Full text (2026-11-08): 42 studies, g = 0.529 overall, but randomised studies g = 0.307 vs non-randomised 1.020; North America 0.149 and Scandinavia 0.180 (CIs cross zero); stronger in elementary; no test-delay analysis.
Conference abstract (not a full article): MOVEOUT cluster-RCT, 20 Danish schools, per-protocol 10 intervention vs 14 wait-list control classes, ages 10–15, ≥5 hours a week of curriculum-based outdoor teaching for one year. Learning: mathematics 0.35 (95% CI 0.07 to 0.63), reading 0.61 (95% CI 0.06 to 1.15); unit not named in the abstract. No significant well-being or motivation change overall.
Abstract: scoping review of 41 studies (10,453 students, preschool to college) from 2,362 records. Outdoor teaching "appears to improve learning" in sciences, reading, writing, social studies and mathematics, and "seems to support" self-awareness, school climate, motivation and well-being. No pooled effect size. Open access, but the full text was not reachable from the box this run.
Systematic review, 13 studies of regular curriculum-based outdoor teaching (≥ 4 h a week for ≥ 2 months): mostly case studies, no randomised trial; only one controlled study used a standardised achievement test (90 US fifth graders, reading/writing higher, p = 0.03, no effect size, maths not reported); no delayed tests; quantitative quality low (0.18). Bounds how much weight the pooled g ≈ 0.5 can bear for outdoor teaching. Full text read 2026-11-02.
Abstract: quasi-experiment, 20 outdoor-teaching classes vs 10 parallel comparison classes, grades 3–6, more than 2.0 hours a week for one school year; reading pre- and post-tested. "A small positive impact on test scores." No effect size in the abstract. Same research programme as OUT-008 (maths, no difference).
Abstract: explorative quasi-experiment, 15 Danish public schools, pupils aged 9–13, 2014–2015; 23 outdoor-maths classes (n = 421) vs 12 outdoor-teaching classes that did not do maths outdoors (n = 198). Both groups improved; no significant difference. Authors: moving maths teaching outside "neither harmed nor improved" maths skills. No effect size in the abstract. Named in open question 23.
Review state: first-pass draft, pending human review.