Menstrual Cycle Length Tracker/Predictor

Inspectable records

Ledger state

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

Area

Biology, Medicine & Pharmacology (educational estimates only — every panel labeled not-medical-advice)

Tranche

tranche-4

Evidence ID

t4-286

Ledger rows

1

No ledger note is attached.

Review findings

NEEDS_REVIEW because the exact ambiguity is: cycle length variability is named as an output but has no formula, and fractional average lengths have no specified date conversion or rounding rule. The honest-label requirement is present and should remain visible on every prediction panel.

Formula and scope findings

• The formula for cycle length variability is missing, so that output cannot be verified or computed.
• The average cycle length may be fractional, but no rule specifies how to convert a fractional number of days into a date-only predicted start date.
• The prediction formula is a simple arithmetic estimate, not a generally reliable physiological prediction; irregular cycles, missing logs, and nonrepresentative history are not addressed.
• No minimum history length or validation rule is specified. At least two chronologically ordered, distinct period-start dates are needed to calculate a cycle length.

Unit assumptions

• Input dates are valid ISO 8601 calendar dates in the proleptic Gregorian calendar.
• Cycle length is the date difference in calendar days between consecutive period starts; the start day is not counted inclusively.
• The average cycle length is measured in days.
• Date arithmetic is timezone-independent and ignores time-of-day and daylight-saving transitions.
• A predicted start is expected to be a calendar date; the specification does not define rounding or timestamp behavior for fractional-day predictions.
• Cycle-length variability has no defined unit or statistical method because no formula is supplied.

Boundary hardening

BREAK_CLAIMED · SELF_FLAGGED

The specification permits or fails to define behavior for invalid and undefined inputs: a zero-length cycle produces a raw prediction unless explicitly rejected, one start date causes a 0/0 average, and cycle-length variability has no formula. Date-counting convention is also unspecified and can shift the prediction by one day.

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": {
    "history_of_period_start_dates": [
      "2025-01-01",
      "2025-01-29",
      "2025-02-26",
      "2025-03-26"
    ]
  },
  "expected_outputs": {
    "predicted_next_start": "2025-04-23",
    "cycle_length_variability": null
  },
  "working": "Differences: 2025-01-29 − 2025-01-01 = 28 days; 2025-02-26 − 2025-01-29 = 28 days; 2025-03-26 − 2025-02-26 = 28 days. Average = (28 + 28 + 28) / 3 = 84 / 3 = 28 days. Next start = 2025-03-26 + 28 days = 2025-04-23. Variability = undefined because no variability formula is provided."
}

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