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C6 weakened

When pupils' own phones and other personal devices are freely available during lessons, pupils learn less in some settings than when the school bans or restricts them (for example by collecting phones), measured on learning outcomes such as test results and grades, but an average effect of restricting them is not established. Gains after bans have been found in some settings and groups (England, driven by the lowest-achieving pupils; girls in Norway; maths in US high schools), while a Swedish study found no improvement, a large preregistered US study of schools that locked pupils' phones away in pouches for the school day found average test-score effects close to zero, ruling out gains larger than about 0.007 standard deviations, with small losses in middle schools (Allcott et al. 2026, a working paper not yet peer reviewed), and classroom-level teacher restrictions in Chile left standardised test scores unchanged (ruling out gains of about 0.03–0.06 standard deviations), with only a modest drop in recreational phone use among eighth graders and a small drop in how capable pupils felt (Shi & Villarroel 2026, a working paper not yet peer reviewed).

Status
weakened
Last change
2026-10-28
Serves
Q2 (How does that work in practice: in school, with screens, and with AI as one of the tools?)
Ages
grundskola-hog, gymnasium (school evidence: England, Sweden grade 9, Norway lower secondary, US middle and high schools including a Florida district and national pouch adopters, Chile grades 8 and 10, Rio de Janeiro grades 6–9); vuxen-livslangt for laboratory mechanism studies and for a large Indian higher-education RCT (Sungu et al. 2026; mean age 19.4, range 16–22)
Area
Screens, devices and attention
Relates to
C6 relates-to C9 (both concern devices in school but they do not overlap: C6 is about rules for pupils' own phones and personal devices during lessons, free access versus a ban or restriction; C9 is about school-provided one-device-per-pupil programmes and average attainment. A study of a 1:1 programme belongs to C9 unless it compares access rules during lessons. They meet where Kessel et al. 2020 suggest that high 1:1 device density may make phone bans less noticeable. Thematic, not a dependency) C6 relates-to C36 (C36 is whether any gain is larger for lower-achieving pupils; C6 is whether an average gain is established. They share sources and settings but ask different questions. Thematic, not a dependency).
Bounds
Scope: pupils' own phones and personal devices that are freely available during lessons, compared with a ban or restriction, measured on learning outcomes (tests, grades), not on calm, wellbeing or reported distraction alone. School-provided 1:1 programmes are C9. Evidence in the project: Beland & Murphy 2016 (England, difference-in-differences: after school phone bans, high-stakes results rose by about 0.07 SD on average, driven by the lowest-achieving pupils, per source note); Abrahamsson 2024 (Norway, lower secondary, staggered difference-in-differences: the average effect was null but masked gains for girls, including grades and externally marked maths, per source note); Kessel et al. 2020 (Sweden, grade 9, difference-in-differences: no improvement in pupil results after school phone bans, rejecting effects of the size Beland & Murphy found); Campbell et al. 2024 (scoping review of 22 studies, no randomised trials, mixed results). Laboratory mechanism evidence with university students, not lessons: laptop multitasking lowered lecture comprehension for the user and for peers who could see the screen (Sana, Weston & Cepeda 2013); the mere presence of one's own smartphone lowered available cognitive capacity (Ward et al. 2017). Bans differ in enforcement: OECD 2024 reports, from correlational data, that where phones are banned about 29 % of students still use a smartphone often (source note). Average-effect bound (added 2026-10-07, nightly attack): Allcott, Baron, Dee, Duckworth, Gentzkow & Jacob 2026 (NBER Working Paper 35132, preprint, not peer reviewed when applied; preregistered staggered difference-in-differences, 1,778 US middle and high schools adopting lockable Yondr pouches in 2023–2025 versus 42,919 never-adopters; full text read): before adoption most adopters had a no-show rule or no rule, and teacher-reported personal phone use in class fell from 61 % to 13 % of pupils; pooled test-score effect −0.006 school-level SD (SE 0.010), about −0.003 student-level SD, ruling out gains above about 0.007 student-level SD; high schools +0.026 (maths +0.047, significant, about 0.024 student-level SD), middle schools −0.025 (significant); at most three years after adoption, school-level outcomes. Classroom-restriction bound (added 2026-10-09, nightly attack): Shi & Villarroel 2026 (EdWorkingPaper 26-1413 / IZA DP 18426, preprint, not peer reviewed when applied; full text read): Chile pre-pandemic classroom-level teacher phone restrictions, within-teacher and within-student designs; grade 8 recreational phone use −3 pp (~4% of mean), grade 10 no behavioural change; test scores near zero (Table 3: grade 8 teacher-FE 0.007 SE 0.026; grade 10 −0.003 SE 0.027; student-FE −0.012 / 0.005), ruling out gains of about 0.03–0.06 SD; grade 8 perceived capability −0.023/−0.022 (~2+ pp, ~3%). Kill-test survived (added 2026-10-09): Figlio & Özek 2025 (NBER WP 34388 / EdWorkingPaper 25-1315, preprint, not peer reviewed when applied; full text read): Florida LUSD all-day backpack ban DiD, high vs low pre-ban Advan smartphone activity; year-2 scores +0.622 percentiles overall (p < .05), spring +1.083, middle/high year 2 +0.905 / spring +1.333; first-year discipline surge then fade; unexcused absences down. Kill fails (scores rose). Correction 2026-10-26: all schools in the district were under the same rule (phones in backpacks for the entire school day, including lunch), and the estimate compares schools with high and low phone activity before the ban, so no group kept free access; the authors call it a lower bound for the policy's effect. Year one showed no significant gain (+0.283 percentiles, SE 0.257), and the year-two gain was not significant for elementary schools (+0.509), girls (+0.455) or Black students (+0.657) (Table 3). Contrast is exposure intensity under one ban, not ban vs no ban. Kill-test survived (added 2026-10-11): Lichand, Moreno-Louzada, da Costa & Gentzkow 2026 (NBER WP 35233, preprint, not peer reviewed when applied; full text read; ATTN-011): Rio de Janeiro city-wide ban on non-pedagogical phone use (classroom phase Aug 2023, school-wide Feb 2024), DiD of middle schools with partial or no prior rules against schools already strict (matched sample 97,380 pupils, 154 schools); maths+Portuguese index +0.061 SD (SE 0.028, p < .05) after the school-wide ban, maths +0.077, Portuguese +0.045 (p < .10); classroom-only phase +0.010 (ns) in the matched sample, but +0.033 (SE 0.016, p < .05) in the full sample (196,757 pupils, 325 schools; Table D11, where the school-wide estimate is +0.044, SE 0.020); with standard errors clustered at the school level instead of school × grade, only the first period after the school-wide ban stays significant, which the authors call "an important caveat" (corrected 2026-10-28); gains concentrated among low prior achievers and grades 7–8. Kill fails (scores rose). Contrast is exposure intensity under one ban, not ban vs no ban. Kill-test survived (added 2026-10-14): Sungu, Choudhury & Bjerre-Nielsen 2026 (Science 394(6820), 178–181, DOI 10.1126/science.aef7249; peer reviewed; full Science page read; ATTN-012): preregistered RCT, 10 HEIs in Odisha, India, Spring 2024; department–grade cohorts randomised to mandatory in-class phone collection vs free access; N = 16,683 students; end-of-semester GPA +0.073 SD [95% CI 0.003, 0.144], one-sided p = 0.021; larger for lower prior performers and first-years; lecture-only ban. Kill fails (grades rose). HEI population, not K–12. Beneito & Vicente-Chirivella 2022 (Spain) remains cited as supporting school-level gains but is not yet a separate source in the project.
Does-not-transfer-to
School-provided one-device-per-pupil programmes (C9).
What would kill this
A field randomised trial or difference-in-differences study in which free access to phones or personal devices during lessons does not lower learning outcomes for the pupil (or for neighbouring pupils) compared with a ban or restriction such as collecting phones. Bank wording (Swedish, verbatim): “Fält-RCT/DiD där fri telefon-/laptopaccess under lektion inte sänker lärande för eleven (och grannar) relativt förbud/låda.”
Tutor consequence
none yet

Attack record

5 attacks: 3 survived, 2 narrowed

2026-10-07 narrowed

Attack
When US middle and high schools moved from mostly no-show or no phone rules to locking pupils' phones in pouches for the whole school day, in-class phone use fell sharply but average standardised test scores did not rise (pooled effect −0.006 school-level SD, ruling out gains above about 0.007 student-level SD), so C6's unconditioned claim that pupils learn less with free access than under a restriction fails on average and its kill-condition is met for this large sample.
Target
kill-condition
Source
Allcott, Baron, Dee, Duckworth, Gentzkow & Jacob 2026 (preprint) | DOI 10.3386/w35132
Steelmans to
C6's kill-condition is a difference-in-differences study in which free access to phones during lessons does not lower learning outcomes compared with a ban or restriction; this preregistered staggered DiD (1,778 adopters vs 42,919 never-adopters, Callaway–Sant'Anna with covariates, parallel pre-trends, robust to refined control groups excluding schools with strict policies or statewide bell-to-bell bans) finds a precisely estimated null on test scores, and together with the Swedish null (Kessel et al. 2020) leaves the average effect unsupported.
Why
Nightly-attacks 2026-10-07 Europe/Stockholm. Full author PDF read (not stored). Contrast: 62 % of adopters (teacher survey) previously had a no-show rule and 23 % none; teacher-reported share of pupils using phones in class for personal reasons fell 61 % → 13 %; GPS phone activity fell ~0.18 log points. Table 3: pooled combined ATT −0.006 (SE 0.010), maths −0.002, ELA −0.006 (≈ −0.003 student-level SD); high schools combined +0.026 (SE 0.017), maths +0.047 (SE 0.018, p < .05; ≈ 0.024 student-level SD); middle schools combined −0.025 (SE 0.012, p < .05), maths −0.026 (p < .05). Kill withheld: (1) working paper, not yet peer reviewed; (2) high-school maths rose in the same study, and gains after bans are reported elsewhere (Beland & Murphy 2016 in England, driven by low achievers; Abrahamsson for Norwegian girls; Figlio & Özek 2025 Florida year 2, Lichand et al. 2026 Rio, Beneito & Vicente-Chirivella 2022 Spain, as reported by Allcott et al.); (3) school-level outcomes, at most three years after adoption, pouches imperfectly enforced, comparison schools not phone-free. Not a restatement: Kessel et al. 2020 was only an open challenge in Bounds and the claim text was unconditioned; this is the first ledger entry on C6. Claim and Bounds rewritten same turn; brief and the practical rule rewritten. Preprint flagged.
Rewrite
claim-field+brief

2026-10-09 narrowed

Attack
In Chilean classrooms where teachers set their own phone rules, restricting phones (never allow, or allow only a few times) left standardised math and reading scores unchanged relative to freer classroom policies (estimates near zero; gains of about 0.03–0.06 SD ruled out), despite a modest drop in eighth graders' recreational in-class phone use, so C6's kill-condition is met for classroom-level restrictions and the residual "some settings" picture needs a classroom null.
Target
kill-condition
Source
Shi & Villarroel 2026 (preprint) | DOI 10.26300/5w3c-ea57
Steelmans to
C6's kill-condition is a field DiD/RCT in which free access to phones during lessons does not lower learning outcomes compared with a ban or restriction; this within-teacher and within-student design finds precisely that for classroom-level teacher restrictions in Chile (null on scores; only modest behavioural change in grade 8), so the claim must record that classroom-level restrictions are another setting where an average learning gain is not established.
Why
Nightly-attacks 2026-10-09 Europe/Stockholm. Full EdWorkingPaper PDF read (not stored). Table 3: Never Allow or Allow a Few Times vs often/always — grade 8 teacher-FE 0.007 (SE 0.026), grade 10 −0.003 (0.027); grade 8 student-FE −0.012 (0.018), grade 10 0.005 (0.016); authors rule out gains of about 0.03–0.06σ. Phone use −3 pp (~4% of mean) in grade 8 only. Capability −0.023/−0.022 (~2+ pp, ~3%) in grade 8. Kill withheld: (1) working paper; (2) classroom-level teacher discretion with uneven compliance, not a school-day collection ban; (3) school-level gains remain (Beland & Murphy 2016; Abrahamsson; Figlio & Özek 2025; Lichand et al. 2026 as reported); (4) many Chilean teachers treat phones as pedagogical tools. Not a restatement of Allcott/Kessel: different country, identification (within-teacher / within-student), and level (classroom vs school-day pouch/ban). Claim and Bounds rewritten same turn; brief and the practical rule Limits rewritten. Preprint flagged.
Rewrite
claim-field+brief

2026-10-09 survived

Attack
In a large Florida school district that banned phones for the whole school day, comparing schools with high versus low pre-ban student smartphone activity, free-er access did not lower learning outcomes relative to the stricter restriction (test scores did not rise after the ban), so C6's kill-condition is met for this district-level ban.
Target
kill-condition
Source
Figlio & Özek 2025 (preprint) | DOI 10.3386/w34388
Steelmans to
C6 dies on a field DiD in which free access does not lower learning outcomes vs a ban/restriction; if Figlio & Özek's high-vs-low activity contrast showed a null or negative effect of the ban on scores, the kill-condition would be met for this US district policy.
Why
Nightly-attacks 2026-10-09 Europe/Stockholm. Full EdWorkingPaper PDF read (not stored). Genuine kill-condition test: DiD of a binding all-day district ban (backpacks/purses all day under Florida's instructional-time law), high vs low pre-ban Advan smartphone activity. Kill fails: year-2 average scores +0.622 percentiles (p < .05); spring-only +1.083; middle/high year 2 +0.905 / spring +1.333; males spring +1.421. First-year discipline surge then fade; unexcused absences down, explaining ~half of middle/high gains (exploratory). Design understates effects (both groups treated). Distinct from Allcott (pouches, average null), Shi (Chile classroom null), Beland & Murphy, Abrahamsson. Claim field unchanged; Bounds note the survive and the Florida gain. Status remains weakened.
Rewrite
none

2026-10-11 survived

Attack
In Rio de Janeiro's municipal middle schools, where a 2023–24 city-wide ban on non-pedagogical phone use hit hardest in schools that had no strict phone rules before, freer prior access did not lower learning relative to the stricter restriction (test scores did not rise after the ban in those schools relative to schools already strict), so C6's kill-condition is met for this middle-income, city-wide ban.
Target
kill-condition
Source
Lichand, Moreno-Louzada, da Costa & Gentzkow 2026 (preprint) | DOI 10.3386/w35233
Steelmans to
C6 dies on a field DiD in which free access to phones during lessons does not lower learning outcomes compared with a ban or restriction; Rio's ban applied to all 1,000+ municipal schools at once (not chosen by each school), quarterly student-level test scores give two years of pre-trends, and if schools moving from partial or no rules to the ban had not gained relative to schools that were already strict, the kill-condition would be met in a large middle-income system.
Why
Nightly-attacks 2026-10-11 Europe/Stockholm. Full author PDF read (27 April 2026 version; not stored). Genuine kill-condition test: DiD of treatment schools (partial or no pre-ban phone rules) against control schools (already strict), grades 6–9; full sample 196,757 students in 325 schools; matched sample 97,380 students in 154 schools, 549,969 student-quarter observations. Principal survey: share of schools where most or all pupils used phones in class fell from 52 % to 19 % (treatment) and from 40 % to 15 % (control). Kill fails: Table D2 (matched sample), school-wide ban × treated on the maths+Portuguese z-score index +0.061 (SE 0.028, p < .05), stable across specifications (0.073 with student fixed effects; 0.084 with CRE × post); maths +0.077 (SE 0.037, p < .05), Portuguese +0.045 (SE 0.024, p < .10); event-study pre-trends flat; gains concentrated among low prior achievers and in grades 7–8, and in schools whose principals reported phone use fell. The earlier classroom-only phase (Q3–Q4 2023) showed no significant effect (+0.010, SE 0.021). The authors' extrapolation to about 0.2 SD against no ban is a calibration from coarse principal reports and is not used here. Limits: working paper; compares exposure intensity under one ban, not ban vs no ban; treatment and control schools differ in baseline levels (treatment schools poorer, about 0.1 SD lower scores); a harder 2024 test applied to all schools; phone use measured by principals' retrospective reports. Not a duplicate: first ledger entry from this study; distinct country, system and identification from Figlio & Özek 2025 (Florida, smartphone-activity terciles), Allcott et al. 2026 (US pouches), Shi & Villarroel 2026 (Chile classroom rules), Kessel et al. 2020 (Sweden). Previously named in Bounds only as reported second-hand by Allcott et al.; now read and a separate source (ATTN-011). Claim field unchanged; Bounds note the survive and the Rio gain. Status unchanged (weakened from earlier narrowings).
Rewrite
none

2026-10-14 survived

Attack
In a preregistered randomised controlled trial of about 17,000 higher-education students in India, mandatory in-class phone collection did not raise end-of-semester grades relative to free phone access during lectures, so freer access did not lower learning and C6's kill-condition is met for this large field experiment.
Target
kill-condition
Source
Sungu, Choudhury & Bjerre-Nielsen 2026 | DOI 10.1126/science.aef7249
Steelmans to
C6 dies on a field RCT/DiD in which free access to phones during lessons does not lower learning outcomes compared with a ban or restriction; this preregistered cohort-randomised RCT (16,683 students, 10 HEIs, lecture-only phone boxes vs business-as-usual) is exactly that design, and if GPA had not risen under the ban the kill-condition would be met in a large middle-income system with peer-reviewed evidence.
Why
Nightly-attacks 2026-10-14 Europe/Stockholm. Science article page read (Vol. 394, Issue 6820, pp. 178–181, published 8 October 2026); Crossref DOI checked; design detail confirmed against the author PDF of the earlier working-paper version (not stored). Genuine kill-condition test: cohort-level randomisation, mandatory phone deposit at lecture start vs free access, end-of-semester GPA with mostly external blind grading. Kill fails: +0.073 SD [95% CI 0.003, 0.144], one-sided p = 0.021; larger for lower prior performers and first-years. Limits: higher education (mean age 19.4), not K–12 pupils; lecture-only ban, not all-day; India HEIs. Not a duplicate: first ledger entry from this study; distinct design (true RCT), country, level (HEI), and peer-reviewed status from Figlio & Özek 2025, Lichand et al. 2026, Allcott et al. 2026, Shi & Villarroel 2026, Kessel et al. 2020. Claim field unchanged; Bounds and Ages note the survive and the India HEI gain. Status unchanged (weakened from earlier narrowings). With this survival C6 reaches the floor of 3 survivals.
Rewrite
none

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.

Linked sources

16 linked sources (6 supports, 9 limits, 1 challenges)

Supports (6)

SourceBasis
ATTN-001 · Ill Communication: Technology, distraction & student performance (2016)England, difference-in-differences (full text): after school phone bans, age-16 exam results rose by 0.064 SD on average (significant only at the 10% level), with the gains among pupils with lower results at age 11; no average effect in maths. Full text checked 2026-11-13.
ATTN-015 · Banning mobile phones in schools: evidence from regional-level policies in Spain (2022)Abstract: Spanish regional bans from 2015, synthetic control and DiD on regional PISA; positive and significant maths and science effects reported for Galicia (0.6–0.8 and about 0.72–1 years of learning), with significant score effects reported only for that region; bullying fell in both. Region-level, not pupil-level. Open access, but the full text was blocked from the box.
ATTN-010 · The Impact of Cellphone Bans in Schools on Student Outcomes: Evidence from Florida (2025 (NBER WP 34388 / EdWorkingPaper 25-1315; working paper, not peer reviewed))Florida district all-day ban DiD (working paper): year-2 test-score gains (~0.6 percentiles overall; spring ~1.1; middle/high spring ~1.3). C6 kill-condition test survived 2026-10-09.
ATTN-011 · The Educational Impacts of School Phone Bans: Evidence from Brazil (2026 (NBER WP 35233; working paper, not peer reviewed))Rio de Janeiro city-wide ban DiD (working paper): maths+Portuguese index +0.061 SD after the school-wide ban in schools without prior strict rules vs already-strict schools; classroom-only phase ns; gains mainly among low achievers. C6 kill-condition test survived 2026-10-11.
ATTN-002 · Laptop multitasking hinders classroom learning for both users and nearby peers (2013 (online 2012))University lab experiment: laptop multitasking lowered lecture comprehension for the user and for peers who could see the screen; not a school lesson study.
ATTN-012 · Phones impede learning: Evidence from a massive phone-free classroom experiment (2026)Preregistered RCT in Indian higher education (Science): mandatory in-class phone collection raised end-of-semester GPA ~0.073 SD vs free access; gains larger for lower prior performers and first-years. C6 kill-condition test survived 2026-10-14.

Limits (9)

SourceBasis
ATTN-007 · Smartphone Bans, Student Outcomes and Mental Health (2024 (NHH SAM 01/24); JHR early view 2026)Norway, lower secondary (full text of the 2024 discussion paper): no average effect on GPA, teacher grades or track; girls gained (GPA +0.08 SD, externally marked maths up to +0.22 SD four years on), more where phones were handed in or kept out; the author cannot reject that girls' and boys' effects are equal. Full text checked 2026-11-13.
MEDIA-019 · Screen Use and Child and Adolescent Development and Mental Health Outcomes (umbrella review) (2026)Correlational: overall screen exposure associated with lower academic achievement (r = −0.15), but it measures general (mostly out-of-school) use, not phone availability in lessons vs a ban. Cannot establish causation; does not test C6. Abstract only.
ATTN-008 · The Effects of School Phone Bans: National Evidence from Lockable Pouches (2026 (NBER WP 35132; working paper, not peer reviewed))Preregistered national US DiD (working paper, not peer reviewed): lockable phone pouches cut in-class phone use but average test-score effects were close to zero (rules out gains > ~0.007 student SD); high-school maths up, middle schools slightly down. C6 weakened 2026-10-07 (average-effect bound).
ATTN-005 · Evidence for and against banning mobile phones in schools: A scoping review (2024)Scoping review: no RCTs; 4 studies found improvement after bans, 3 found no difference.
ATTN-013 · School phone policies and their association with mental wellbeing, phone use, and social media use (SMART Schools): a cross-sectional observational study (2025)Cross-sectional comparison of 20 restrictive vs 10 permissive English secondary schools (1,227 pupils aged 12–15): no significant difference in teacher-rated odds of being below target in English (adjusted OR 1.45, 95% CI 0.85–2.47, p = 0.18) or maths (1.01, 0.45–2.27, p = 0.98). Not a before/after or randomised design; attainment is a teacher rating, not a test score.
DIG-006 · Students, digital devices and success (2024)Correlational: phone bans reduce reported distraction on average, but where phones are banned about 29 % still use a smartphone often; effects depend on compliance.
ATTN-014 · Reexamining the “brain drain” effect: A replication of Ward et al. (2017) (2022)Preregistered direct replication of Ward et al. 2017 Experiment 2 (N = 383): no effect of smartphone location on OSpan, F(2, 377) = 0.10, p = .91, or on go/no-go performance. The mere-presence mechanism cited in C6's Bounds did not replicate. Laboratory undergraduates, not school lessons.
ATTN-009 · The Consequences of Cellphone Restrictions in Classrooms (2026 (EdWorkingPaper 26-1413 / IZA DP 18426; working paper, not peer reviewed))Chile classroom-level teacher restrictions (working paper): null on standardised scores (rule out ~0.03–0.06 SD); modest grade-8 recreational-use drop; small capability drop. C6 weakened 2026-10-09 (classroom-restriction bound).
ATTN-003 · Brain Drain: The Mere Presence of One’s Own Smartphone Reduces Available Cognitive Capacity (2017)University lab: the mere presence of one's own smartphone lowered available cognitive capacity; a mechanism, not a learning outcome in lessons.

Challenges (1)

SourceBasis
ATTN-006 · The Impact of Banning Mobile Phones in Swedish Secondary Schools (2019 (IFN WP 1288); publicerad Economics of Education Review 2020)Swedish DiD: no improvement in pupil results after school phone bans; rejects effects of the size Beland & Murphy found.

Review state: first-pass draft, pending human review.