{"id":1434,"slug":"text-generation-eg-2023-no-effect-beyond-900-words","title":"Text-generation meta-analysis (Educational Psychology Review 2023) — Hedges g ≈ .41; LARGEST for 301-600 word texts; NO EFFECT beyond ~900 words","kind":"reference","scope":"business","status":"current","audiences":["kevin","smb-owner","candid-team"],"topics":["editorial-discipline","generation-effect"],"reference_body":"**Claim:** **Text-generation meta-analysis (*Educational Psychology Review* 2023)**: **Hedges g ≈ .41**, not attributable to time-on-task; **largest for 301-600 word texts** and **NO effect beyond ~900 words**.\n\n**Source:** Educational Psychology Review (2023).\n\n**Confidence:** Verified (meta-analysis).\n\n**Caveat:** Length ceiling is the critical practical limit.\n\n**Why this matters for Candid:** Counsel against very-long-form input tools — the generation effect ceilings beyond ~900 words. Practical implication: **keep input fields short and focused**; if a tool needs many inputs, break into screens (also supports [[rule-design-for-goal-gradient]] from Brief E).","rationale_body":null,"metadata":null,"links":{"outgoing":[{"slug":"bertsch-2007-generation-effect-meta-d-0-40","title":"Bertsch, Pesta, Wiscott & McDaniel (2007), Memory & Cognition 35(2) — 86-study generation-effect meta: d ≈ 0.40 (\"almost half a standard deviation\"); LARGER at longer retention (d ≈ 0.64 for >1 day)","kind":"reference","scope":"business","link_type":"relates-to"}],"incoming":[{"slug":"research-brief-engagement-mechanisms-top-up-smb-june-2026","title":"Research notes (capture-layer top-up): why interactive online tools are psychologically engaging — six additional mechanisms (June 2026)","kind":"research-notes","scope":"business","link_type":"relates-to"},{"slug":"caveats-engagement-mechanisms-top-up-mechanism-vs-business-outcome","title":"Caveats for the engagement-mechanisms top-up: strong independent evidence sits at the MECHANISM level not the business-outcome level; nearly every effect is moderated","kind":"reference","scope":"business","link_type":"relates-to"},{"slug":"rule-make-user-generate-not-just-pick","title":"R4 — Where appropriate, make the user GENERATE inputs (not just pick from menus) — the generation effect d≈0.40 is real but ceilings beyond ~900 words and doesn't scale to expository text","kind":"rule","scope":"business","link_type":"depends-on"}]},"created_at":"2026-06-20T19:24:15.960Z","updated_at":"2026-06-20T19:24:15.960Z"}