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C4 weakened

Written comments that tell learners what is right or wrong in their work and how to improve it (task and process feedback) lead to better performance on a later task or test than a grade or score given on its own, or than praise on its own, at least on open-ended tasks. On a simple speed task, one classroom experiment found grades alone did as well as comments (Butler & Nisan 1986).

Status: weakened
Last change: 2026-11-14
Serves: Q1 (How do humans actually learn, and what helps them learn best?)
Ages: grundskola-lag, grundskola-hog, gymnasium, vuxen-livslangt, overgripande (the project's evidence is reviews and meta-analyses spanning school and higher education)
Area: Teaching and feedback
Relates to: C4 relates-to C0 (C0 requires corrective feedback during retrieval practice; C4 is about which kind of feedback helps, not about retrieval versus restudy. Thematic, not a dependency).
Bounds: Task-type bound added 2026-10-16 (week run): in Butler & Nisan 1986 (261 grade-6 pupils, nine classes), grades alone matched comments on a later quantitative word-construction task, while comments beat grades on a qualitative divergent-thinking task. Reworded 2026-10-16 (9 consecutive fruitless searches): the claim now names the comparison the studies in the library actually run — comments versus grades-only or praise-only, measured on a later task or test — as in Butler 1988 (grades 5–6, comments beat grades and grades-plus-comments at a later session) and Koenka et al. 2021 (grades versus comments; delay of the achievement measures not verified). This claim is about the type of feedback (information about the task and the process versus praise, grades or scores alone), not about whether retrieval practice with corrective feedback beats restudy (that is C0), and not about who gives the feedback: AI-generated versus human feedback is a separate question (Kaliisa et al. 2025 found no significant difference on performance, per source note). Evidence in the project: Hattie & Timperley 2007 (feedback at four levels; task, process and self-regulation feedback effective, feedback about the self, such as praise, least effective); Kluger & DeNisi 1996 (meta-analysis of 607 effects from 131 papers, lab, work and school tasks, full text read: feedback raised performance by d = 0.41 on average but over 38 % of effects were negative; in the trimmed set of 470 effects, feedback that included praise did much less, d = 0.09 (80 effects) against 0.34 without, and the quarter of feedback most threatening to self-esteem d = 0.08 against 0.47 for the least threatening quarter; but normative feedback, such as a grade or comparison with others, was not a significant moderator, process feedback was too rare to test (6 effects) and no delayed-learning moderator was coded, so it compares feedback with no feedback, not comments with grades, and does not test this claim's kill line; corrected 2026-11-09); Lipnevich & Smith 2009 (464 first-year university students revising a course-exam essay one week after the draft, feedback in hand: detailed comments raised the revised score strongly, η² = .24; cell means 83.85 with instructor comments alone against 75.11 with a grade alone and 74.38 with praise alone; the outcome was a revision of the same essay, and the authors state there was no later assessment or similar later task, so it supports the direction of this claim outside its "later task or test" scope, not a test of the kill line; its grade-related effects are small and are held in open question 24); Wisniewski, Zierer & Hattie 2020 (meta-analysis: high-information feedback about task and process gave much larger effects than reinforcement or punishment, d ≈ 0.99 versus d ≈ 0.24 per source note); Shute 2008 (review: focus feedback on the task, not the learner; praise sparingly; avoid grades that crowd out comments); Black & Wiliam 1998 (formative assessment). These are reviews and meta-analyses that mix immediate and later outcomes. Kill-condition test survived 2026-11-14: Abe & Usami 2024 (Japanese Journal of Behaviormetrics 51(1), 45–54, DOI 10.2333/jbhmk.51.45; full text and the authors' per-study coding table read), a meta-analysis restricted to post-tests given some time after the feedback (9 studies, 32 effects, school settings, mostly 1970–1987 plus one 2017 university study; USA, Israel, Germany, Venezuela): teachers' written comments beat a numeric grade alone, g = 0.42 (95% CI 0.17 to 0.66), with very high heterogeneity (I² = .90); praise-type comments ("very good") did .53 worse than task-level comments (p = .04). Age bound (limit, not a narrowing): the advantage shrank by about .07 per year of the learners' age (p < .001); the large effects come mainly from Butler's grade 5–6 experiments with a later session within about two days, while in the longest classroom study (Krampen 1987, maths over a school year, about age 14) subject-matter comments beat grades by only 0.22 and 0.00. The praise-alone comparison on a later test has still not been tested in this project.
What would kill this: A meta-analysis, or a well-powered randomised study, in which learners given a grade or score alone, or praise alone, perform as well as or better than learners given task and process comments on a later task or test (a delayed test or a later piece of work done without new feedback). Reworded 2026-10-16 from the bank wording (meta-analysis where generic or ego feedback systematically beats task/process feedback on delayed learning in K–12), which kept producing fruitless searches.
Tutor consequence: none yet

Attack record

2 attacks: 1 survived, 1 narrowed

Reworded on 16 October 2026 (a change of wording, not an attack, so it is not counted). After 9 nightly searches in a row found no study that could test the old wording: no study found where a grade, score or praise alone was compared with task/process comments on a later test in the form the old wording and bank kill sentence asked for (generic/ego feedback systematically beating task/process feedback, K–12 meta). The new wording names the comparison the library's studies run (Butler 1988; Koenka et al. 2021; Panadero & Sánchez-Iglesias 2025 holds comments constant and varies grades) and keeps the claim's spirit. No new data added.

2026-10-16 narrowed

Attack: In a class-randomised experiment with 261 sixth-graders, pupils who had received only numerical grades did as well as pupils who had received task-related comments on a later quantitative task done without feedback, which meets C4's kill-condition for that kind of task.
Target: kill-condition
Source: Butler & Nisan 1986 | Journal of Educational Psychology 78(3), 210–216, DOI 10.1037/0022-0663.78.3.210
Steelmans to: C4 dies where grades alone match task/process comments on a later task done without new feedback; Butler & Nisan ran exactly that comparison on two task types.
Why: Week run 2026-10-16, cycle 1 (widened-search slot) Europe/Stockholm. Full text read (not stored). Nine classes, three per condition (comments, grades, no feedback). Session 3 work, no feedback expected. Task A (quantitative word construction): Session 3 scores similar for comments and grades, both above no feedback (t = 12.30, p < .001); comments above grades only on the long-words subscore (p < .013). Task B (qualitative divergent thinking): comments above grades and no feedback (t = 15.68, p < .001). Kill withheld because comments won on the open-ended task; narrowed to open-ended tasks. Limits: nine classes, analysed at pupil level; "later" is hours to two days. Not a preprint. Resets C4's fruitless streak.
Rewrite: claim-field+brief

2026-11-14 survived

Attack: In the only meta-analysis restricted to post-tests given some time after the feedback, comparing teachers' written comments with a numeric grade alone in school settings (9 studies, 32 effects), learners given only a grade would do as well as learners given comments — which would meet C4's kill-condition for the comments-versus-grade comparison.
Target: kill-condition
Source: Abe & Usami 2024 | Kodo Keiryogaku (The Japanese Journal of Behaviormetrics) 51(1), 45–54, DOI 10.2333/jbhmk.51.45 (published PDF, gold open access on J-STAGE, full text read 2026-11-14; authors' per-effect coding table on OSF, osf.io/94jk5; Crossref-checked)
Steelmans to: C4 dies if, across studies that measure a later test rather than a same-task revision, a bare grade matches written comments; the earlier evidence behind C4 mixed immediate and later outcomes, and an independent random-effects synthesis with a moderator analysis (age, feedback type, test type, stakes) and very high heterogeneity is the fairest available test — it could show the classic advantage shrinking to nothing once old, small or praise-type studies are weighed.
Why: Nightly-attacks 2026-11-14 Europe/Stockholm (widened-search slot; C4 had 7 consecutive fruitless searches). Full text: inclusion required written teacher feedback on a test or work, a verbal-feedback group versus a numeric-rating group, a post-test given after an interval following the feedback, and a school setting (pp. 46–47). Random-effects g = 0.42 (95% CI 0.17 to 0.66, p = .002), τ² = .39, I² = .902; fixed-effect 0.38; Bayesian 0.42 (0.17 to 0.67); Egger intercept p = .70 (pp. 50–51). Meta-regression (Table 1, p. 52; reference task-level comments): age −.07 per year (−.12 to −.04, p < .001); self-level (praise-type, e.g. "very good") −.53 (−1.03 to −.04, p = .04); process-level .04 (ns, 3 effects); factual/procedural tests −.47 (p = .06); high-stakes post-test −.41 (p = .07). Kill fails: comments beat grades on later tests, and task-level comments did better than praise-type comments. Caveats: 9 studies, mostly 1970–1987, USA/Israel/Germany/Venezuela; several unpublished dissertations; the largest task-comment effects are Butler's Israeli grade 5–6 experiments (later session within about two days); in the longest classroom study (Krampen 1987, maths over a school year) subject-matter comments beat grades by only 0.22 and 0.00 (OSF table); the advantage shrinks with age. Not a duplicate (prior entries: Butler & Nisan 1986 weakened; Kluger & DeNisi / Lipnevich & Smith corrected). Not a restatement of the open-ended-task bound (this tests the main comparison). Not a preprint. Claim field and kill line unchanged; Bounds get an evidence line and the age limit; the practical rule Limits updated. Status unchanged (weakened). Resets C4's fruitless streak (7 → 0).
Rewrite: none (bounds evidence line only)

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.

9 November 2026 — C4's limits summarised Kluger & DeNisi 1996 from the source note and implied that feedback drawing attention to the self (including normative feedback such as grades) weakens effects; the full text shows praise and self-esteem threat do, normative feedback does not significantly, and the meta-analysis does not compare comments with grades.

Linked sources

14 linked sources (11 supports, 3 limits)

Supports (11)

Source	Basis
FB-021 · A Meta-analysis of the Effects of Verbal Feedback by Teachers on Academic Performance and Moderating Effects (2024)	Meta-analysis of 9 studies (32 effects) restricted to post-tests given some time after the feedback: teachers' written comments beat a numeric grade, g = 0.42 (0.17 to 0.66); praise-type comments did .53 worse than task-level comments; advantage smaller for older learners (-.07 per year of age). Kill-condition test, C4 survived 2026-11-14. Full text read.
FB-002 · Assessment and Classroom Learning (+ populärsammanfattning Inside the Black Box) (1998)	Listed as relevant to this belief; no one-line summary has been written yet.
FB-008 · Enhancing and undermining intrinsic motivation: The effects of task-involving and ego-involving evaluation on interest and performance (1988)	Grades 5–6, 12 classes randomised: comments gave the highest interest and performance, including at a later session without expected evaluation; grades and grades-plus-comments undermined both (abstract). Classic basis for C4; small cluster design.
CRE-007 · Rewards and creative performance: A meta-analytic test of theoretically derived hypotheses (2012)	Adjacent (creativity, not learning): rewards help creative performance more when paired with task-focused, informative feedback and choice; controlling or completion-based rewards slightly hurt. Consistent with C4's task/process feedback over bare grades; does not test a later learning outcome. Abstract only.
FB-001 · The Power of Feedback (2007)	Four feedback levels: task, process and self-regulation feedback effective; feedback about the self (praise) least effective.
FB-006 · How does artificial intelligence compare to human feedback? A meta-analysis of performance, feedback perception, and learning dispositions (2025 (online 24 sep 2025; Educational Psychology 2026, 46(1)))	Indirect: compares AI-generated with human feedback (no significant difference on performance), not task/process feedback with praise or grades.
FB-004 · The effects of feedback interventions on performance: A historical review, a meta-analysis, and a preliminary feedback intervention theory (1996)	Meta-analysis (131 papers, 607 effects; lab, work and school tasks): feedback raised performance by d = 0.41 on average, but over 38% of effects were negative; praise (d = 0.09 vs 0.34) and threats to self-esteem weakened effects, while normative feedback such as grades was not a significant moderator. Compares feedback with no feedback, not comments with grades. Full text checked 2026-11-09.
FB-007 · A meta-analysis on the impact of grades and comments on academic motivation and achievement: a case for written feedback (2021 (online 2019))	Four meta-analyses (elementary and secondary school): students receiving grades had poorer achievement and motivation than students receiving comments; grades beat no feedback on achievement but lowered motivation (abstract). Delay of the achievement measures not verified.
FB-011 · Effects of Differential Feedback on Students' Examination Performance (2009)	University students revising an exam essay a week later with feedback in hand: detailed comments raised the revised score strongly (η² = .24); instructor comments alone 83.85 vs grade alone 75.11 vs praise alone 74.38. Same-task revision, no later task, so outside C4's "later task or test" scope; not a kill test. Full text read.
FB-005 · Focus on Formative Feedback (ETS RR-07-11; journalversion RER 2008) (2007 (ETS-rapport); 2008 (Review of Educational Research, 78(1), 153–189))	Listed as relevant to this belief; no one-line summary has been written yet.
FB-003 · The Power of Feedback Revisited: A Meta-Analysis of Educational Feedback Research (2020 (online 22 jan 2020; Front. Psychol. 10:3087))	Meta-analysis: high-information feedback (task and process) far larger than reinforcement or punishment.

Limits (3)

Source	Basis
FB-020 · Effects of No Feedback, Task-Related Comments, and Grades on Intrinsic Motivation and Performance (1986)	Grades alone matched task comments on a later quantitative speed task; comments won on the qualitative task.
FB-009 · ManyClasses 1: Assessing the Generalizable Effect of Immediate Feedback Versus Delayed Feedback Across Many College Classes (2021)	Adjacent: across 38 college classes, immediate vs delayed feedback made no difference to later class-assessment scores (0.002, HDI −0.05 to 0.05). Feedback timing, not type; does not test C4. Abstract only.
FB-010 · Impact of Displaying Grades Vs. Not Displaying Grades on Academic Performance and Emotional Outcomes While Delivering Feedback Comments: A Longitudinal Study (2025)	Secondary school (99 students, four intact classes, about 92 analysed): with brief comments on every task, the class that started seeing grades scored lower on the next task (5.40 vs 6.80 out of 10), and the gap was gone one task later (6.86 vs 6.73). Grades+comments vs comments, no grade-only arm, so not a kill-test of C4. Full text checked 2026-11-11.

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