What Is Supersession? Part Number Supersession in Product Data
Supersession is what happens when a manufacturer replaces one part number with another. This glossary entry covers the shapes (one-to-one, split, merge), direction, what a supersession record needs, and how it differs from equivalence.
Part number supersession is what happens when a manufacturer replaces one part number with a new one. The old number is discontinued; the new one is the designated successor. In catalog data, supersession is a directed relationship: old → new, with an effective date, a quantity ratio and a source.
A customer searches your webshop for part AB-1001. The manufacturer discontinued it six months ago and replaced it with AB-2050. If your catalog does not carry that supersession as a typed, dated record, the customer sees “no results” or “out of stock” — and buys from whoever does carry the link. That is the operational cost of treating supersession as tribal knowledge instead of data.
Definition
Supersession is a manufacturer’s declaration that one part number replaces another. It is distinct from equivalence (a different manufacturer’s interchangeable part) and from compatibility (a part that works alongside, not in place of, another). The relationship-types guide calls this edge REPLACED_BY.
The shapes of supersession
Not every supersession is a simple swap. The common patterns:
| Shape | What happens | Illustrative example |
|---|---|---|
| One-to-one | Part A is replaced by Part B | AB-1001 → AB-2050 |
| One-to-many (split) | One old part becomes two or more new parts | Kit KT-300 splits into KT-300A (seals) + KT-300B (hardware) |
| Many-to-one (merge) | Several old parts collapse into one new number | AB-1001 and AB-1002 both become AB-2050 |
| Quantity change | The successor has a different pack size or unit of measure | AB-1001 (pack of 10) → AB-2050 (pack of 5), quantity ratio 2:1 |
Every shape needs the quantity ratio recorded. A split without ratios means someone orders one of the new part when they need both. A merge without ratios means someone orders one when they need two.
One-way versus two-way
Supersession is almost always one-way: the manufacturer says B replaces A, but that does not mean A replaces B. The old part is discontinued; the new part may have a wider specification, a different material or an updated design. Treating the relationship as bidirectional — as many spreadsheet crosswalks do — creates the risk of quoting a discontinued part as a substitute for the current one.
Two-way interchangeability is a separate, stronger claim. It belongs under EQUIVALENT_TO, not REPLACED_BY, and it requires its own evidence. See supersession vs interchangeability vs equivalence.
What a supersession record needs
A bare “old → new” mapping is better than nothing, but it is not trustworthy enough to automate. A complete supersession record carries:
| Field | Why it matters |
|---|---|
| Old part ID | The discontinued number |
| New part ID | The successor number |
| Direction | One-way (default) or explicitly bidirectional |
| Effective date | When the change took effect — critical for historical orders |
| Quantity ratio | How many of the new part replace one of the old (or vice versa) |
| Reason | Design change, regulatory, consolidation, rebranding |
| Source | Manufacturer bulletin, price-list diff, supplier notice |
| Status | Active, pending review, rejected |
Before and after
| Before (spreadsheet crosswalk) | After (typed supersession record) |
|---|---|
| AB-1001 → AB-2050 (cell note: 'replaced') | old: AB-1001, new: AB-2050, direction: one-way, date: 2026-03-01, qty ratio: 1:1, source: manufacturer bulletin #412, status: active |
| No history of intermediate steps | Chain: AB-1001 → AB-1500 → AB-2050, each link dated and sourced |
| No way to tell who decided this | Source and review fields on every link |
Where Claro fits
Claro stores supersession as a REPLACED_BY edge in the Product Identity & Evidence Graph, with direction, date, quantity ratio, source and confidence on every link. When a customer or an agent searches for a discontinued part, the graph resolves the chain to the current successor and presents it with the evidence behind each step — no spreadsheet lookup, no phone call to the product specialist who retired last year.
Related
Glossary
Spare Parts Data Glossary
All the terms in one table.
Guide
Model supersession chains
The data model, chain resolution, splits, merges and what the old SKU should return.
Comparison
Supersession vs interchangeability vs equivalence
Who decides, direction, evidence and risk.
Article
Supersession: the most under-modeled relationship
Why catalogs still hold supersession in people's heads.
FAQ
What is part number supersession?
Part number supersession is when a manufacturer officially replaces one part number with a new one. The old number is discontinued and the new one is the designated successor. A supersession record captures the old ID, new ID, direction, effective date, quantity ratio and source.
What is the difference between supersession and equivalence?
Supersession follows one manufacturer’s lineage: the maker says part B replaces part A. Equivalence crosses manufacturers: a third party or the catalog team says part X from Brand 2 is technically interchangeable with part A from Brand 1. The evidence, risk and direction are different.
Can supersession be one-to-many or many-to-one?
Yes. A one-to-many split means one old part is replaced by two or more new parts (for example, a kit split into individual components). A many-to-one merge means several old parts collapse into a single new number. Both require quantity ratios to be recorded.
Claro
See how Claro handles this in production
This concept is one piece of keeping a catalog trusted. See how Claro resolves identity, enriches missing attributes, and validates every update before it reaches your PIM or ERP.
Learn more