Duplicate customer records mostly exist because the same address is stored in different ways, so matching logic never links them. Standardising every address to a single Royal Mail PAF form — and attaching a UPRN where available — creates a consistent key that lets you match and merge duplicates reliably, then validation at entry stops new ones appearing.
Why do duplicate records keep appearing?
Duplicates form because free-text addresses have no single correct format. The same household is entered as "Flat 2, 10 High St", "10 High Street Apt 2" and "10 High St" — three records your system treats as different people.
- Inconsistent formatting of the same address
- Abbreviations, casing and punctuation differences
- Missing sub-premises splitting one household
- Multiple imports with no shared address key
- No canonical identifier to match against
How does address standardisation enable deduplication?
Normalise every address to its canonical PAF form first, then compare. Once records share an identical, standardised address — ideally with a UPRN — matching becomes confident rather than fuzzy, so you can merge with far fewer false positives.
Fuzzy name match vs standardised address match
| Method | Reliability | Notes |
|---|---|---|
| Name-only matching | Low | Misses moves and duplicates common names |
| Raw address matching | Medium | Breaks on formatting differences |
| Standardised PAF / UPRN | High | Consistent canonical key |
How do I deduplicate and keep records clean?
Start by cleaning the backlog with address data cleansing to standardise every address, which also tackles the wider problem of bad CRM data. Then add CRM address validation at entry so new records are captured in a consistent form and duplicates never return.
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Frequently asked questions
What causes duplicate customer records?
Duplicates form when the same customer is entered more than once with slightly different details — usually a differently formatted address. Because addresses are free-text, one household can appear as several records that never match.
How do standardised addresses help deduplication?
When every address is normalised to a single Royal Mail PAF form (and ideally a UPRN), records for the same premises share an identical key. That consistent key lets matching logic confidently merge duplicates that would otherwise look different.
What is address deduplication?
Address deduplication is the process of identifying and merging records that refer to the same location. It relies on standardising addresses first, so comparisons are made against a consistent, canonical format rather than raw free-text.
Can a UPRN be used as a dedupe key?
Yes. A UPRN is a unique identifier for each addressable location in the UK, so matching on UPRN is a highly reliable way to group records for the same premises.
How do I stop duplicates from coming back?
Validate addresses at the point of entry with PAF-verified lookup so every new record is standardised from the start. Consistent input is what prevents fresh duplicates after a clean-up.
How many UK addresses can be matched against?
Royal Mail PAF covers ~31M UK delivery points across ~1.8M postcodes, giving deduplication a comprehensive, authoritative reference for standardising and matching addresses.
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