{
  "independentScientificReview": "pending",
  "qualifiedExternalReview": "pending",
  "claims": [
    {
      "id": "C1",
      "text": "Agreement depends on the tested activity and sampling procedure; there is no single transferable accuracy number for a wrist device.",
      "sources": [
        "S1",
        "S2",
        "S3"
      ],
      "type": "Bounded narrative inference",
      "support": "S1 selected Results 231–243; S2 Results 212 and limitations 224; S3 Table 2 and Results 317.",
      "limit": "Heterogeneous cohorts and historical models; no pooled estimate or causal comparison of populations."
    },
    {
      "id": "C2",
      "text": "A small average signed error can hide substantial absolute error.",
      "sources": [
        "S3"
      ],
      "type": "Direct numerical illustration and interpretation",
      "support": "S3 Table 2, Fitbit treadmill row: ECG-minus-device mean 0.5 bpm; absolute paired mean 8.2 bpm; 120 repeated readings.",
      "limit": "40 participants assigned this wrist model; repeated observations are not 120 independent people. No confidence interval inferred from SD."
    },
    {
      "id": "C3",
      "text": "Steady-state readings and handrail-assisted measurements do not establish accuracy during unrestricted exercise or rapid transitions.",
      "sources": [
        "S1",
        "S2",
        "S3"
      ],
      "type": "Applicability inference from Methods",
      "support": "S1 final-minute stages; S2 handrail and two-minute procedure; S3 selected steady-state times.",
      "limit": "No claim that every device fails during transitions; direct transition validation needed."
    },
    {
      "id": "C4",
      "text": "These studies do not establish current hardware or firmware performance, calorie accuracy, clinical benefit, or safe heart-rate treatment thresholds.",
      "sources": [
        "S1",
        "S2",
        "S3"
      ],
      "type": "Scope boundary",
      "support": "Historical model identities; criterion-validation designs and selected heart-rate outcomes.",
      "limit": "No recommendation to substitute a device for clinical monitoring."
    }
  ],
  "withheld": [
    "S1 walking below-5% device count: source inconsistency",
    "S2 exact concordance values: malformed decimals in retrieved text",
    "Thiebaud quantitative values: age eligibility and endpoint-definition ambiguities",
    "Van Oost 2025 and intense-exercise 2023: Methods inaccessible",
    "All current-model rankings and subgroup equivalence claims"
  ]
}