{
  "schema": "schym-story-contract/v1",
  "slug": "to-charge-or-not-to-charge",
  "title": "To charge, or not to charge?",
  "revision": "r6",
  "language": "en",
  "publication_date": "2026-09-19",
  "research_cutoff": "2026-09-18",
  "driving_question": "How much can an electric-car adoption curve tell us about the next sale, the next policy shock, and the cars already on the road?",
  "reader_role": "investigator",
  "primary_story_engine": "forensic-timeline",
  "truth_contract": "empirical",
  "interaction_required": true,
  "signature_interaction": {
    "name": "The Diffusion Road / Mineral field guide",
    "action": "Learn the three questions and the data's denominators, then inspect the Diffusion Road's independently normalized registration and fleet rails. Select monthly or trailing-year registrations and explicitly enter the conditional future. Draw a five-year continuation before revealing the historical record. A separate illustrative curve laboratory matches ceilings and peak gains so that the shape assumption becomes visible before the forecast test. All substantive choices travel in the shared URL.",
    "editorial_job": "Distinguish fast-changing new-car flows from slow-moving active stock without silently aligning different reference dates.",
    "persistent_specimen": "Germany's passenger-car market, carried from monthly registrations through forecast failures, registered keepers, district stock and an explicitly hypothetical fleet-turnover scenario."
  },
  "convenient_explanation": "Once electric cars pass a tipping point, a stable S-curve tells us when the whole fleet will become electric.",
  "failure_and_repair": "Country paths diverge after the same threshold; forecasting gains change with horizon; policies interrupt registrations; a fitted sales ceiling cannot replace the stock-flow identity. Repair the explanation with explicit denominators, out-of-sample benchmarks, source-date discipline and transparent fleet scenarios.",
  "evidence_boundary": {
    "observed": "KBA revised registrations and active stock; OWID's rounded IEA country shares; Census regional characteristics.",
    "derived": "Ratios of sums, threshold dates, market-weight decompositions, keeper differences and stock-flow residuals.",
    "modelled": "The supplied package's rolling-origin forecasts, profile loss, regression estimates and dependence-sensitive uncertainty, attributed as supplied analyses.",
    "scenario": "Constant-fleet turnover arithmetic with explicit future sales paths and assumed BEV exit rates; not a forecast.",
    "reader_sketch": "A retrospective, user-editable five-year drawing, or its explicitly labeled starter template. Neither is an empirical estimate, a blind forecast nor evidence of forecasting skill.",
    "proxy": "Registered keeper address, homeownership and dwelling structure do not measure vehicle use, charging access or household motivation.",
    "unavailable": "Household first-adoption histories, complete real-time data vintages, transaction prices, causal subsidy effects and mutually exclusive import/export/scrappage flows.",
    "illustration": "Original unbranded car artwork and a proposed Blender cutaway communicate the mechanism, not measurements or a real vehicle specification."
  },
  "portable_result": "Restorable URL plus a downloadable text evidence receipt with Road selections, market comparison mode, illustrative curve inputs and the threshold exercise's market, five sketch values, reveal state and paired mean absolute errors when revealed. Revision-bearing article, data/model/figure reading guides and full source/derived-data exports; prior revisions retained.",
  "technology_route": {
    "shell": "Existing Next.js Server Component and site chrome.",
    "islands": "A small URL-restorable scrollytelling stage, reading-progress navigation, synchronized timeline and deferred D3/SVG evidence instruments. Sixteen hash-addressed figure payloads load on proximity or focus, with a bounded JSON stream, checksum, schema and revision check. One loaded spec serves both interaction and exact values. The default static evidence survives a failed request, with an explicit retry. Native observers and the existing reduced-motion hook; no new animation framework.",
    "rejected": "No new chart framework, decorative WebGL, live data endpoint, invented household simulator or background model fitting.",
    "blender": "A documented proposed scene, not an unproduced scene advertised as a working 3D model."
  },
  "mobile_composition": "A cool silver-blue/midnight editorial hero states the question before the instruments. Stack data passports, model definitions, image-supported panels and per-figure guides. Keep the takeaway and its scope note in one content column, never in the narrow label rail. Use full-width charts and explicit non-sticky story steps on short or narrow screens. Direct labels become an adjacent legend; ranked regional views and exact tables remain available.",
  "accessibility_route": "Semantic article, visible focus, native range/select controls, one roving-focus entry per dense chart, hover/focus/tap parity, exact-value disclosures, source-linked captions, explicit reduced-motion and print/no-JavaScript reading paths.",
  "performance_budget": {
    "initial_story_js_gzip_kb_target": 180,
    "deferred_module_gzip_kb_target": 350,
    "media": "Original lightweight SVG; no external fonts, raw workbooks or research ZIP in the runtime.",
    "field_vitals": "LCP <= 2.5 s, INP <= 200 ms, CLS <= 0.1 are targets, not claimed field measurements."
  },
  "evidence_sequence": [
    "The two clocks: new registrations versus active fleet",
    "Countries take different roads, even after the same threshold",
    "Growth is not mechanically determined by current penetration",
    "A curve must beat a simple forecast",
    "Germany's policy chronology and frozen forecast paths",
    "China's scale and the global accounting decomposition",
    "Private and commercial registration markets",
    "The district atlas and the limits of infrastructure correlations",
    "Saturation parameters fail their inspection",
    "Fleet arithmetic and the cars that survive",
    "Research, failure boundaries, reproducibility and a Blender scene proposal"
  ],
  "source": {
    "name": "EV_Diffusion_Research_Package_2026-09-18.zip",
    "sha256": "e5e67eb8a7bfa34620f6b6e0f608537a449a18a4acff5e3745a1d865acee674a",
    "edition": "2026-09-18",
    "preservation": "Original archive is unchanged; only reviewed, rights-appropriate extracts enter the website."
  }
}