Race Time Predictor (Riegel Formula)

Inspectable records

Ledger state

The current ledger marks this instrument verified clean within the source-bound verification corpus.

Area

Everyday & Life

Tranche

tranche-4

Evidence ID

t4-211

Ledger rows

1

No ledger note is attached.

Review findings

The formula T2 = T1 × (D2/D1)^1.06 is the standard Riegel-style prediction formula when both distances share units and both times share units. Verdict is NEEDS_REVIEW because the specification does not explicitly define distance units, time units, pace units, output formatting, or rounding policy. The honest-label warning is appropriate; the cited Pete Riegel 1977 source should be given as a complete bibliographic citation.

Formula and scope findings

No additional record

Unit assumptions

• D1 and D2 must use the same distance unit; the distance ratio is unitless.
• T1 and T2 must use the same time unit; test vectors use decimal minutes.
• Predicted pace means predicted time divided by target distance, expressed in minutes per distance unit.
• The exponent 1.06 is treated as a fixed empirical exponent; it is not universally valid for every athlete, distance, or extrapolation range.
• The specification does not define display rounding or whether pace should be formatted as decimal minutes or minutes:seconds.

Boundary hardening

BREAK_CLAIMED · SELF_FLAGGED

Zero or negative/invalid distances can produce undefined results, and a zero target distance produces an undefined pace even though the time expression evaluates mathematically to zero. The specification does not state input validation or unit conventions, creating rejection and interpretation hazards.

Errata and corrections

No applied erratum is attached to this unique-name record.

Inspectable example

4 review vectors are recorded. One source-bound sample is shown below.

{
  "inputs": {
    "known_distance": 5,
    "known_distance_unit": "km",
    "known_time": 25,
    "known_time_unit": "min",
    "target_distance": 10,
    "target_distance_unit": "km"
  },
  "expected_outputs": {
    "predicted_time_min": 52.1233,
    "predicted_pace_min_per_km": 5.2123
  },
  "working": "D2/D1 = 10/5 = 2. T2 = 25 × 2^1.06 = 25 × 2.08493 = 52.1233 min. Pace = T2/D2 = 52.1233/10 = 5.2123 min/km."
}

Related workflows

Sources and evidence

These pointers bind the page to evidence. They do not grant authority or collapse verification into deployment.

• VERIFIED_LEDGER.json · VERIFIED_CLEAN
• evidence-tranche4/tranche4-results.json
• BOUNDARY_HAZARD_CATALOG.json