Define what a match means
Two products can have similar titles and still serve different comparisons. A different capacity, finish, bundled accessory, or warranty can change the offer. Start by deciding whether your task needs an exact item match or a broader comparison of substitutes.
Keep those relationship types separate in the data. An exact-match price watchlist and a substitute assortment study can both be useful, but they answer different questions. A single generic match flag hides the distinction.
Use identifiers as evidence, not decoration
Google’s GTIN guidance explains the role of manufacturer-assigned trade item identifiers and advises against guessing an identifier when it is uncertain. Where a valid identifier is available, preserve it with the source rather than inventing one to complete a record.
Schema.org distinguishes product properties such as SKU, brand, GTIN, and manufacturer part number. Store them in separate fields. A seller’s internal SKU is not automatically a shared identifier across independent stores.
| Relationship | What to record |
|---|---|
| Exact match | Identifiers and matching variant attributes |
| Substitute | The use case and accepted differences |
| Possible match | Evidence still requiring review |
| No match | The reason it was excluded |
Resolve variants and quantities explicitly
Treat size, color, model revision, capacity, and pack quantity as fields, not details to infer from a thumbnail later. A product page may list many variants while its displayed price reflects only the default selection.
If you compare a pack with a single unit, retain the original price and quantity alongside the normalized per-unit calculation. A bundle that contains different accessories may remain a substitute even if its main item matches exactly.
- Keep the exact selected variant and source reference.
- Record the evidence behind the relationship type.
- Give ambiguous matches a review state.
- Retest matches when product attributes or page structure change.
Audit the match set before aggregating it
Review examples from every match type, including unmatched products. A comparison can look precise while excluding the difficult items that would change its interpretation. Report the denominator: which products were considered, which matched, and which were left out.
Version the matching rules and keep the reviewer’s reason with a correction. When the same comparison is repeated, a changed rule should be visible alongside a changed price. A reviewable product map is the foundation for a useful market observation.
Sources & further reading
This is a practical framework. Numerical examples are illustrative, not observations of a named retailer. Check current platform documentation before applying product-specific requirements.
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