CPY-019 Heuristic layer: content_system

Test one causal variable at a time when possible

IF an experiment must identify what caused a result, THEN change one primary variable or use a designed multivariate test with adequate traffic ELSE treat results as directional.

Why the rule exists

Confounded variants cannot reveal which change caused the outcome.

Condition

The rule fires when this evaluates true. Paths marked below must be present in the fact base; the engine reports the rest rather than guessing them.

experiment.goal eq "causal_attribution"

Facts this rule reads

Fact paths read by CPY-019 and whether the analyser derives them
Path	Source
`experiment.goal`	You supply it

Then

design — target experiment
qualify — target experiment.result, value "directional_only"

Else

retain — target current_text, No triggering condition is present.

LAKA

Smallest sufficient intervention

Yes

Primary axes

Sources

Scientific Advertising — Claude C. Hopkins
Testing, measurement, offers, and accountable advertising.

The raw rule record

Verbatim from 16-copywriting-rules.json. Also available at /v1/rules/CPY-019.

{
  "id": "CPY-019",
  "name": "Test one causal variable at a time when possible",
  "domain": "copywriting",
  "layer": "content_system",
  "strength": "heuristic",
  "human_logic": "IF an experiment must identify what caused a result, THEN change one primary variable or use a designed multivariate test with adequate traffic ELSE treat results as directional.",
  "when": {
    "path": "experiment.goal",
    "operator": "eq",
    "value": "causal_attribution"
  },
  "then": [
    {
      "action": "design",
      "target": "experiment",
      "options": [
        "single_primary_variable",
        "powered_multivariate"
      ]
    },
    {
      "action": "qualify",
      "target": "experiment.result",
      "when": "confounded",
      "value": "directional_only"
    }
  ],
  "else": [
    {
      "action": "retain",
      "target": "current_text",
      "reason": "No triggering condition is present."
    }
  ],
  "unless": [],
  "because": "Confounded variants cannot reveal which change caused the outcome.",
  "diagnostics": [],
  "examples": {},
  "source_ids": [
    "BK-033"
  ],
  "laka": {
    "smallest_sufficient_intervention": true,
    "primary_axes": [
      "scope",
      "depth",
      "magnitude",
      "reversibility"
    ]
  }
}