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Address Data Quality

NCOA: Processing Address Changes at Scale

40 million Americans move each year. NCOA (National Change of Address) processing updates mailing lists to keep them current.

## The Moving Problem

Every year, roughly **40 million Americans** change their address. For businesses that maintain mailing lists, this means databases decay at a rate of about **12% per year** — and mailing to old addresses wastes money.

## What Is NCOA?

NCOA — National Change of Address — is a USPS database that contains the forwarding addresses filed by individuals and families when they move. The database covers moves from the past **48 months**.

## How NCOA Processing Works

| Step | Description |
|------|------------|
| Submit list | Mailer sends address list to licensed NCOA processor |
| Match | Processor compares against NCOA database |
| Update | Moved addresses replaced with new addresses |
| Flag | Unmatched addresses flagged for review |
| Report | Summary of moves, no-matches, and errors |

## NCOA Variants

| Product | Scope | Licensing |
|---------|-------|----------|
| NCOALink | Full NCOA, batch processing | Licensed to ~400 processors |
| ACS (Address Change Service) | Per-mailpiece, real-time | Available to all mailers |
| ANKLink | 48-month+ moves | Supplementary |

## USPS Requirements

The USPS requires NCOA processing for certain mailings:

- **First-Class Presort** — NCOA within 95 days before mailing
- **Marketing Mail** — NCOA within 95 days before mailing
- **Standard Mail** — NCOA optional but recommended

Failure to meet the 95-day requirement can result in loss of postal discounts.

## Privacy Considerations

NCOA data is tightly controlled:

- Only licensed processors can access the full database
- Individual lookups are not available to the public
- Data is encrypted in transit and at rest
- Processors must sign USPS privacy agreements
- The USPS does not share NCOA data with non-postal entities

## Impact

Regular NCOA processing typically updates 8-12% of a mailing list. For a list of 100,000 addresses, that's 8,000-12,000 corrections — each one preventing wasted postage and improving customer communication.

Key Terms

Address Standardization Bulk Mail CASS Certification NCOA

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Frequently Asked Questions

Where can I learn more about postal code systems?
ZipFYI's Stories section features in-depth articles about postal code systems worldwide, their history, how they work, and why they matter. Topics range from the origins of ZIP codes to how modern postal systems handle millions of packages daily.
How do postal code systems evolve over time?
Postal code systems evolve to accommodate population growth, urbanization, and changes in mail volume. New codes are created when areas develop, codes may be reassigned when delivery routes change, and entire systems can be reformed (as Ireland did with Eircode in 2015).
Why are postal codes important for businesses?
Businesses use postal codes for shipping and logistics, sales tax calculation, market analysis, customer demographics, delivery zone determination, insurance underwriting, and compliance with regulations. Accurate postal codes reduce delivery failures and improve customer experience.
How do postal codes relate to demographics?
In the US, the Census Bureau links demographic data to ZIP Code Tabulation Areas (ZCTAs). This enables analysis of population, income, education, housing, and commute patterns at the postal code level. Marketers, researchers, and policy makers rely on this data extensively.
What is geocoding and how does it relate to postal codes?
Geocoding converts addresses and postal codes into geographic coordinates (latitude/longitude). It enables mapping, distance calculations, delivery routing, and spatial analysis. Postal codes serve as a common input for geocoding services because they provide approximate location data.