What counts as the same product
States are joined by a valid normalized GTIN. Records with invalid codes or sharply conflicting identities are quarantined. A shared barcode is strong evidence, but not proof: codes can be reused and upstream databases can contain errors.
What gets compared
We preserve raw ingredients and normalize only case, spacing, Unicode, and trivial punctuation before parsing top-level entries. Nutrition values are compared only on equivalent bases after unit conversion. Package and serving values must parse to compatible mass, volume, or count dimensions.
Noise thresholds
Formatting-only edits do not become events. Nutrients must cross both a 5% relative threshold and an absolute threshold: 5 kcal for calories, 10 mg for sodium, and 0.5 g for the tracked macronutrients. Mass or volume changes must exceed 1% and one gram or milliliter.
Significance and confidence
Significance describes how much label information changed. Confidence describes how strongly the available source history supports the comparison. Public events require significance of at least 30/100 and confidence of at least 55%.
What Label Delta does not claim
An observed change can be a new package, corrected data, or a possible formulation change. We do not infer ingredient quantities, health effects, dietary quality, or allergy safety.