C36 Phone bans and lower achievers

Inside the circle: the core of the claim. Outside: every bound and carve-out in the claim file, numbered, with the attack that forced or added it where the record shows one.

forced by a narrowing attackin the original wordingwritten at creation, or added without a narrowing

Warm cards in the list were added by later attacks; plain cards were in the original draft or written at creation.

1. Scope: school bans or restrictions of pupils' own phones during lessons, compared with freer access, measured on test results or grades, split by prior achievement.

   Written when the claim was created (12 November 2026); not forced by an attack

2. Not about calm, wellbeing or reported distraction alone.

   Written when the claim was created (12 November 2026); not forced by an attack

3. School-provided 1:1 programmes are C9.

   Written when the claim was created (12 November 2026); not forced by an attack

4. C6 covers whether an average gain is established; this claim is about who gains more.

   Written when the claim was created (12 November 2026); not forced by an attack

5. Evidence that shows the pattern, from studies that split by prior achievement: Beland & Murphy 2016 (Labour Economics 41, 61–76, DOI 10.1016/j.labeco.2016.04.004; full text): England, difference-in-differences; high-stakes age-16 scores rose by 6.41% of a standard deviation on average (0.0641 in the most flexible specification); by prior achievement quintile at age 11, the lowest quintile gained 0.1423, the second 0.0986, the third 0.0654, the fourth 0.0229, and the top quintile −0.0254 (not significant).

   Written when the claim was created (12 November 2026); not forced by an attack

6. The authors report that the top quintile was neither helped nor harmed.

   Written when the claim was created (12 November 2026); not forced by an attack

7. Limits of this study (full text, corrected 2026-11-13): the average rise is significant only at the 10% level (0.0641, SE 0.0373; Table 4); by subject (Table 10), the lowest quintile's gain came from subjects other than English and maths (+0.1652, SE 0.0451), while in English and maths together it was +0.0273 (not significant), smaller than the second to fourth quintiles (+0.0635, +0.0538, +0.0388), and in maths alone the lowest quintile fell (−0.0726, SE 0.0238, p < 0.01; mean maths effect 0.0035); looser rules (phones off or on silent) helped the lowest quintile more than strict bans (+0.3052 vs +0.1085; Table A.1); the age-14 outcome rose 0.0245 (not significant).

   Added with attack #1 (corrected; it did not narrow the claim) · Beland & Murphy 2016 · 13 November 2026

8. So the pattern holds on total exam results, not shown for English and maths, and reversed in maths, in this study.

   Added with attack #1 (corrected; it did not narrow the claim) · Beland & Murphy 2016 · 13 November 2026

9. Lichand, Moreno-Louzada, da Costa & Gentzkow 2026 (NBER WP 35233, preprint, not peer reviewed when added; full text): Rio de Janeiro city-wide ban; school-wide phase +0.061 SD overall in the matched sample.

   Written when the claim was created (12 November 2026); not forced by an attack

10. Table D3, full sample, school-wide ban by baseline grade quartile: bottom 0.080 (SE 0.046, p < .10), then 0.040, 0.010, 0.003; classroom phase, bottom 0.062 (SE 0.025, p < .05).

    Written when the claim was created (12 November 2026); not forced by an attack

11. In the matched sample the same school-wide figures were 0.099, 0.078, 0.044, 0.040, none significant.

    Written when the claim was created (12 November 2026); not forced by an attack

12. The authors say effects are concentrated at the bottom of the pre-ban distribution.

    Written when the claim was created (12 November 2026); not forced by an attack

13. Contrast is exposure intensity under one ban, not ban vs no ban.

    Written when the claim was created (12 November 2026); not forced by an attack

14. Sungu, Choudhury & Bjerre-Nielsen 2026 (Science 394(6820), 178–181, DOI 10.1126/science.aef7249; peer reviewed; Science page read): preregistered RCT in Indian higher education, end-of-semester GPA +0.073 SD overall; larger and significant among students below median prior achievement, near zero and not significant above.

    Written when the claim was created (12 November 2026); not forced by an attack

15. Higher education (mean age 19.4), not school pupils; lecture-only ban.

    Written when the claim was created (12 November 2026); not forced by an attack

16. Subgroup point estimates are not quoted from the earlier working paper, whose overall estimate (0.086) already differs from the Science article.

    Written when the claim was created (12 November 2026); not forced by an attack

17. Related but not a prior-achievement split: Abrahamsson 2024/2026 (Journal of Human Resources early view, DOI 10.3368/jhr.0224-13403r2; NHH SAM 01/24 full text): Norway lower secondary, average effect null; girls' GPA +0.08 SD, teacher grades +0.09, externally marked maths +0.22; larger for girls whose fathers had vocational education (GPA +0.09 to 0.14 SD three and four years after).

    Written when the claim was created (12 November 2026); not forced by an attack

18. No effect on boys, but the author “cannot reject the null hypothesis that the coefficients between girls and boys are equal, in any of these results” (discussion paper p. 22); girls' GPA +0.08 is p = 0.064 and teacher grades +0.09 p = 0.05; maths +0.07 (p = 0.067) one year after, +0.22 (p = 0.014) four years after; under strict bans girls' GPA +0.12 (p = 0.032) and maths +0.25 (p = 0.028); no never-treated schools, 40% of schools linked (corrected 2026-11-13 from the discussion-paper full text; the published JHR tables not yet read).

    Added with attack #1 (corrected; it did not narrow the claim) · Beland & Murphy 2016 · 13 November 2026

19. The split is by gender and father's education, not prior test scores.

    Written when the claim was created (12 November 2026); not forced by an attack

20. Evidence already on file that limits or points against the pattern, recorded here and not applied as an attack: Kessel, Hardardottir & Tyrefors 2020 (Economics of Education Review 77, 102009, DOI 10.1016/j.econedurev.2020.102009; IFN WP 1288 full text): Sweden grade 9, no average improvement; no individual test scores, so prior achievement could not be tested.

    Written when the claim was created (12 November 2026); not forced by an attack

21. Using school-level socioeconomic status as a proxy, the lowest quintile had test scores +0.251 (SE 0.101) and a 3.328 percentage-point drop in failing maths; merit points −0.063 (not significant).

    Written when the claim was created (12 November 2026); not forced by an attack

22. The authors say these may be chance and that the event graph is not convincing.

    Written when the claim was created (12 November 2026); not forced by an attack

23. Allcott, Baron, Dee, Duckworth, Gentzkow & Jacob 2026 (NBER Working Paper 35132, preprint, not peer reviewed when added; full text): US schools adopting lockable pouches; limited systematic heterogeneity in pre-registered subgroups; no positive pooled test-score effect for any subgroup examined; in middle schools, negative effects were more pronounced among higher-achieving schools (not pre-registered; school-level baseline achievement, not pupil-level).

    Written when the claim was created (12 November 2026); not forced by an attack

24. Shi & Villarroel 2026 (EdWorkingPaper 26-1413 / IZA DP 18426, preprint, not peer reviewed when added; full text): Chile, classroom-level teacher restrictions; test scores near zero; no systematic differential effects by prior achievement, gender or socioeconomic background.

    Written when the claim was created (12 November 2026); not forced by an attack

25. Goodyear et al. 2025 (The Lancet Regional Health – Europe 51, 101211, DOI 10.1016/j.lanepe.2025.101211; CC BY, full text read): 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 to 2.47, p = 0.18) or maths (1.01, 0.45 to 2.27, p = 0.98).

    Written when the claim was created (12 November 2026); not forced by an attack

26. Not a before/after or randomised design, and no split by prior achievement; attainment is a teacher rating, not a test score.

    Written when the claim was created (12 November 2026); not forced by an attack

27. Figlio & Özek 2025 reports year-two score gains but has no prior-achievement split in the published subgroups.

    Written when the claim was created (12 November 2026); not forced by an attack

28. Laboratory “mere presence” findings (Ward et al. 2017) did not replicate in a preregistered direct replication (Ruiz Pardo & Minda 2022, Acta Psychologica 230, 103717, DOI 10.1016/j.actpsy.2022.103717; CC BY full text; N = 383; OSpan location F(2, 377) = 0.10, p = .91).

    Written when the claim was created (12 November 2026); not forced by an attack

29. This claim is about school test results, not mere presence in the lab.

    Written when the claim was created (12 November 2026); not forced by an attack

30. Added 2026-11-12 on Jonatan's yes, as a distinct claim from C6, with an empty ledger; not attacked in the same turn.

    Written when the claim was created (12 November 2026); not forced by an attack

31. Does not transfer to: School-provided one-device-per-pupil programmes (C9).

    Written when the claim was created (12 November 2026); not forced by an attack

    Average effects of phone bans, which are C6.

0 of 31 bounds and carve-outs were forced by a specific attack.