{
  "schema": "vedokrok.public-item.v1",
  "release_id": "MHC-RPUB-20260920-75ad787a",
  "url": "/knowledge/change-one-difficulty-dimension-at-a-time",
  "id": "MHC-D-RESEARCH-9013",
  "version": "0.1.0",
  "title": "Change one difficulty dimension at a time",
  "summary": "Harder is informative only when you know what became harder.",
  "kind": "heuristic",
  "body": "Increase one meaningful demand—case ambiguity, time pressure, number of variables, independence, or transfer distance—while holding the others roughly stable. Observe the result before stacking another demand. This produces a cleaner signal about which capability has reached its limit.",
  "limits": [
    "Real tasks can combine many demands. The one-dimension rule is for diagnosis and training design, not a claim that authentic performance is simple."
  ],
  "topics": [
    "union-skill-acquisition-career-dominant-focus"
  ],
  "intents": [],
  "source_ids": [
    "RS-05CB28C0C7CF56B3",
    "RS-6958B9284DD609A1"
  ],
  "evidence": [
    {
      "claim": "A meta-analysis of adaptive training found that effects varied by instructional intervention, with adaptive difficulty showing the strongest results among the examined categories.",
      "source_id": "RS-05CB28C0C7CF56B3",
      "role": "supports",
      "note": "The literature was heterogeneous and much of the context was military training; this does not validate every adaptive-learning product.",
      "locator": "Abstract"
    },
    {
      "claim": "A 2025 meta-analysis found that lower-prior-knowledge learners benefited more from higher instructional assistance, while higher-prior-knowledge learners benefited more from lower assistance.",
      "source_id": "RS-6958B9284DD609A1",
      "role": "supports",
      "note": "The effect is moderated by domain and educational status, and does not prescribe a single assistance threshold.",
      "locator": "Abstract and highlights"
    }
  ],
  "use_when": [
    "When practice becomes harder in several ways at once and a performance drop is impossible to interpret."
  ],
  "avoid_when": [
    "Real tasks can combine many demands. The one-dimension rule is for diagnosis and training design, not a claim that authentic performance is simple."
  ],
  "example": "An analyst first removes hints from a diagnostic case. Only after independent accuracy stabilizes does the practice add a shorter time limit.",
  "check": "The next adjustment can be linked to one observed performance change rather than to a bundle of simultaneous changes.",
  "sources": [
    {
      "id": "RS-05CB28C0C7CF56B3",
      "title": "Adaptive training instructional interventions: A meta-analysis",
      "url": "https://pubmed.ncbi.nlm.nih.gov/39083372/"
    },
    {
      "id": "RS-6958B9284DD609A1",
      "title": "A cornerstone of adaptivity – A meta-analysis of the expertise reversal effect",
      "url": "https://www.sciencedirect.com/science/article/pii/S0959475225000660"
    }
  ],
  "relations": [
    {
      "from": "MHC-D-RESEARCH-9013",
      "to": "MHC-D-RESEARCH-9022",
      "type": "useful_with",
      "url": "/knowledge/add-target-constraints-after-the-core-decision-is-stable"
    }
  ],
  "collections": [
    {
      "id": "RC-EA04F47374E04549",
      "title": "Learn new skills, turn them into career evidence, and protect the main development edge",
      "url": "/collections/learn-new-skills-turn-them-into-career-evidence-and-protect-the-main-development-edge"
    }
  ]
}