Address Quality Best Practices: From Entry to Delivery

By Adam Collinson

Address Quality Series · Article 7 of 8 · [See all articles →]

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I recently worked with a company that had invested heavily in CASS™ processing and NCOA^Link®. Their just-in-time address quality processes were excellent. Yet they were still not getting discounts on as much mail as they would like and having a higher rate of undeliverable mail than they wanted. Turns out their data entry processes were fundamentally broken. 

There are only so many issues that CASS™ can resolve. Otherwise, it is garbage in, garbage out, as they say.

In another case, the issue was not the quality of the address but rather its compliance with industry-specific regulations. There are multiple industries that have restrictions on the types of addresses that can be used and when. So, I’ll evaluate addresses to identify both high- and low-quality addresses that fail the mailer’s legal requirements. Part of the solution is to then find the holes in their processes that are allowing these addresses into their systems.

These experiences reinforce a critical truth: address quality isn’t a single process. It’s a lifecycle that begins the moment an address enters your system and continues through database maintenance, just-in-time processing, mailing, and return mail handling.

Excellence at one stage means nothing if you’re failing at another. 

Let me walk you through the complete lifecycle and the best practices that separate organizations achieving modest results from those achieving exceptional ones.

Stage One: Address Entry and Getting It Right the First Time

The cheapest and most effective place to ensure address quality and correct address-related issues is at the point of entry. Every address that enters your system correctly is one you don’t have to try to fix later.

This requires more than just asking people to type in their addresses. It requires real-time validation, intelligent form design, and user-friendly interfaces that guide people toward providing complete, correct information.

Implement address verification at the point of entry. 

When someone types an address into your website, mobile app, or data entry screen, validate it immediately. Modern APIs can standardize and verify addresses in real-time, catching errors before they enter your database. Once you have a quality address, you can check the characteristics of the address to ensure that it is in compliance with your needs and requirements, or if you need to ask for a different or additional address.  

For example, your business provides a service that involves installation at a physical location, such as heating and cooling services. You also offer follow-up and other services for which you want to send reminders and information. You see that the address is a valid physical location, so you are prepared for delivery and installation. However, then you discover that the address is not valid for mail delivery, so you know to ask for a second address, such as their mailing address.

But make the experience user-friendly. Don’t just reject invalid addresses. Suggest corrections. If someone types “123 Main St” and your validation system determines that there is missing secondary data, instead of just “Address Error, please reenter” you can provide guidance “This address requires secondary data (APT, STE, UNIT…), please add that information”. 

Designing Helpful Error Messages

When I was in college and writing programs, you had to debug code by eye. I had a program that was failing. I knew why; I was using the wrong variable name somewhere on this one page of code. But I could not find it. So, I asked a friend to look for ___________ on this page. They found it in a matter of seconds. 

Now, imagine an input address of “123 MIAN ST APT 45…” and an error message of just “Invalid Address”. The user, “but that is my house number and apartment number…”.  People can, sometimes, look over the obvious; their brain is autocorrecting without them being aware.  But, what if the message was “Invalid street name, please verify”. That puts the focus directly to “MIAN” and the needed correction to “MAIN”.  

Messages that guide users to the solution they need are much more appreciated and effective than those that just feel like “you’re wrong, try again”:

• Design forms that capture the information you need: If you’re in an industry that requires physical addresses, include validation rules that flag or reject various types of non-physical addresses (like PO BOX Addresses). If you need secondary information for high-rise buildings, make those fields prominent and clear.
• Provide contextual help: When someone is entering an address, a small note saying “Please include your apartment or unit number if applicable” can significantly reduce missing secondary information issues.
• Train your staff if addresses are being entered manually: They should understand the difference between primary and secondary information, know how to handle unusual addresses, and recognize when additional information is needed.

The goal at this stage is simple: capture complete, correct addresses from the start that meet your business needs. Every dollar invested in data entry quality saves multiple dollars in cleanup, correction, and undeliverable mail costs later – not to mention potential fines and penalties.

Stage Two: Database Maintenance and Working to Maintain Quality

Addresses don’t stay current forever. People move. Businesses relocate. New construction gets added to USPS databases. Streets get renamed. 

Even if you capture perfect addresses at entry, decay happens over time.

Database maintenance is an ongoing process, not a one-time event. The question isn’t whether to maintain your address data. The question is how frequently and how thoroughly.

To maintain address quality over time, organizations should:

• Run regular CASS™ processing on your database, even for addresses you’re not mailing to immediately. This keeps your data current and identifies issues before they become mailing problems.
• Process your database through NCOA^Link® on a regular schedule. Don’t wait until you’re about to mail. Proactive move updates maintain database quality over time, especially when you do not mail to every address on a regular basis.
• Let regular processing inform database cleanup decisions. If an address repeatedly fails CASS™ validation or NCOA^Link® repeatedly flags an address with MLNA or BCNO, that’s a signal to investigate, reach out through alternative channels, update the record, or suppress it.

• Use your own data. ACS™ returns from prior mailings are gold for database maintenance. When you get ACS™ confirmation that an address is invalid, update your database immediately. When you get a new address through ACS™, apply it to your database so future mailings benefit.
• Create exception and correction processes. When data entry staff or customer service agents learn about address changes through customer interactions, capture that information and update your database. These organic updates are often more current than formal CASS™ or NCOA^Link® processing.
• Build proprietary address databases for your high-value customers. If you mail to the same addresses repeatedly, maintain detailed records about what works and what doesn’t. Document special delivery instructions, note addresses with unusual characteristics, flag situations where carriers have provided specific guidance.

The key principle at this stage is continuous improvement. Your database should get better over time, not worse. If it gets worse, that suggests a problem in some other process.

Stage Three: Just-in-Time Processing Before Mailing

Even with excellent data entry and thorough database maintenance, just-in-time processing as close to the time of mailing is essential. This is where you catch the most recent changes.

To make the most of just-in-time processing, organizations should:

• Run CASS™ processing on every mailing. This is mandatory for postage discounts and provides the most current validation information.
• Run NCOA^Link® processing as close to the mailing date as practical. The USPS receives over 100,000 COA filings a day. The shorter the gap between processing and mailing, the fewer moves you’ll miss.
• Use just-in-time processing to make mailing decisions, not just to update your database. Let CASS™ codes, NCOA^Link® results, and integration with prior ACS™ data determine which pieces you mail, suppress, or handle differently.
• Incorporate prior ACS™ data into your just-in-time decisions. Treat addresses that recently generated ACS™ returns differently from those with no prior issues.
• Leverage your proprietary address database information. Factor in any documented special characteristics or delivery requirements for specific addresses.
• Create custom suppression rules based on your business needs. Your regulations, business model, and customer relationships should guide which addresses you mail and which you suppress.

This stage is where compliance meets strategy. You’re not just qualifying for discounts. You’re making intelligent decisions about resource allocation.

Stage Four: Mailing With the Right Service Endorsements

Once you’ve decided to mail a piece, selecting the appropriate service level and endorsements matters.

For operational mail (statements, bills, notices), First-Class Mail with appropriate ACS™ endorsements ensures you get return information about undeliverable pieces as well as the handling you desire (forward, return all, secure destruction). Using ACS™ closes the loop and provides data faster for future improvements – even with pieces the USPS forwards and delivers to a new address.

For marketing mail where you want undeliverable information, again, use ACS™.  Be very careful with your STID and Endorsement selection.  The wrong choice can trigger undesired handling and significant additional costs.  Many mailers do not want to print the Endorsement that is required on Marketing pieces using ACS™. The cost and impact of these endorsements is often well justified by the value of the data you receive.

For marketing mail where you don’t need undeliverable information but want to track overall deliverability, using ACS™ with an endorsement that lets the USPS dispose of the undeliverable pieces is the way to go.

Match your endorsements to your business needs and budget. Not every piece needs the same level of tracking and delivery information. Segment your mail and apply endorsements strategically.

USPS  provides a detailed description of the various address correction options available within basic/nonautomation and full-service mailings and the STIDs that provide the different undeliverable-as-addressed (UAA) treatments.

Remember that timing affects deliverability. Mailing during seasonal volume peaks (holidays, tax season) can impact deliverability rates, especially for addresses with known deficiencies or characteristics that require extra carrier attention. Consider timing in your strategy.

Stage Five: Undeliverable Mail Handling and Closing the Loop

What happens after mailing is just as important as what happens before.

Capture undeliverable data systematically. Whether through physical returns, ACS™ electronic notifications, or a combination, ensure this information flows back into your systems. This isn’t optional for organizations serious about address quality.

NOTE: If you mail, you will get physical returns. It does not matter if you used Secure Destruction or endorsements and classes of mail that allow the USPS to dispose of pieces; you will still get some physical returns. So, you need a plan for handling physical returns: 1) Interpret physical markings, 2) convert them into actionable data, and 3) feed them into the same workflow as ACS.

Process ACS™ returns promptly to maximize its value. Applying COA results sooner means fewer pieces need to get detected and forwarded by the USPS – improving customer satisfactions and retention, response rate and revenue flow, and even fraud risks.

Route ACS™ information appropriately within your organization. Customer service teams need to know about UAA mail. Database administrators need to update records. Marketing teams need to understand campaign performance. Fraud prevention teams need visibility into suspicious address patterns.

Take action based on ACS™ reason codes. Different codes require different responses. We covered this extensively in the ACS™ article, but the key point is that capturing data without acting on it provides no value.

Secure destruction of physically returned mail containing sensitive information is critical, especially in regulated industries. Have clear processes for handling returns that contain PII, financial information, or healthcare data.

Use mail tracking when available. Use of Informed Visibility^® enables tracking of individual pieces through the postal system. This provides visibility into delivery timing and success rates that can inform operational decisions.  Often, this will flag a potential delivery issue even before you get an ACS™ record.

The Integration Challenge

The biggest obstacle to implementing these best practices isn’t understanding what to do. It’s integrating these stages into a cohesive system.

Data needs to flow between stages. Address entry validation should access current CASS™ and NCOA^Link® data. Database maintenance should incorporate ACS™ returns. Just-in-time processing should leverage both database maintenance results and ACS™ history. Return mail handling should feed back into database updates and data entry quality metrics.

This requires both technology and process. The technology needs to connect systems that are often siloed. The process needs to define who does what, when, and how information flows.

Most organizations don’t have this level of integration initially. That’s okay. Start with improving individual stages, then work on connections between stages over time.

Process Monitoring and Continuous Improvement

Best practices aren’t static. They evolve. 

USPS operations change. Regulations shift. Business models adapt.

Implement process monitoring and trending. Track key metrics over time:

• Data entry error rates and types.
• Database decay rates between maintenance cycles.
• CASS™ validation results and trends.
• NCOA^Link® match rates and types.
• ACS™ return rates and reasons.
• Overall deliverability by segment and address characteristic.

Compare results across different list sources, campaigns, and time periods. This analysis reveals patterns and opportunities that aren’t visible in individual mailing reports.

Use these insights to continuously refine your processes. If data entry errors in secondary information are consistently high, that indicates a training or interface design issue. If certain address characteristics correlate with poor deliverability, that informs future segmentation and suppression decisions.  Additionally, if certain address characteristics have higher response rates – use to impact future mailing list requests.

Create feedback loops where learnings from backend processes provide information to front end operations. If ACS™ returns consistently show missing secondary information from a particular source, go back to that source and improve data capture requirements. Or, the next time they log in or call customer support, have an alert appear on their account.

The Role of Defined Processes

Best practices require documentation. Not just high-level principles, but specific, documented processes that define:

• How addresses are validated at entry.
• How frequently database maintenance occurs.
• What triggers exception handling.
• How just-in-time processing decisions are made.
• How return mail is processed and routed.
• Who is responsible for each step.

Without defined processes, address quality depends on individual knowledge and initiative. That doesn’t scale, and it’s vulnerable to personnel changes.

Document your processes. Train your staff. Update documentation as you learn and improve, and as the industry and data changes. Make address quality a systematic capability rather than a personal responsibility.

The Four-Pillar Framework

Think about address quality work in four pillars, each representing a different stage in the lifecycle:

1. Address Entry. This includes data verification, customer service (web, email, phone), and any process where addresses enter your system.
2. Database Maintenance. This includes regular CASS™ processing, NCOA^Link® updates, application of ACS™ data, proprietary database updates, and exception correction processes.
3. Just-in-Time Processing. This includes final CASS™ and NCOA^Link® runs right before mailing, decision engine logic that determines which pieces to mail, integration with prior ACS™ data, and final segmentation and suppression.
4. Processing what actually happened to the mail piece after mailing.  This involves capturing and initiating actions from ACS™ data received as well as physical returns.

Behind these pillars is a foundation of process monitoring. You need trending and comparison capabilities that span all stages, enabling you to see patterns and make informed improvements.

This framework helps organizations think systematically about address quality rather than treating it as a disconnected set of compliance tasks.

Working with Partners

Most organizations don’t handle all stages of this lifecycle internally. They work with partners for data entry validation, CASS™ processing, NCOA^Link® updates, mail preparation, or ACS™ data management.

When selecting partners, evaluate their capabilities across the entire lifecycle, not just individual services. A partner who can run CASS™ processing but doesn’t help you interpret results and make decisions provides limited value. A partner who processes NCOA^Link® but doesn’t integrate that data with CASS™ results and ACS™ history is missing opportunities.

At GrayHair Software, we work with clients across all stages of the address quality lifecycle. We help design data entry validation strategies, provide database maintenance services, guide just-in-time processing decisions, and manage ACS™ data capture and application. But more importantly, we help connect these stages into an integrated system that continuously improves over time.

The partner you choose should bring expertise, not just execution. They should challenge your assumptions, suggest improvements, and help you achieve results that exceed basic compliance.

The ROI of Best Practices

Implementing best practices across the address data quality lifecycle requires investment. Technology, processes, training, and ongoing management all cost money and time.

But the return on that investment is substantial. Reduced undeliverable mail saves postage and production costs. Improved deliverability increases response rates and revenue flow. Better customer data supports fraud prevention and regulatory compliance. Enhanced customer experience from receiving mail reliably builds loyalty and retention.

The organizations achieving best practice results aren’t lucky. They’re systematic. They’ve invested in the lifecycle approach and reaped the benefits.

Getting Started

If your organization isn’t operating at best practice levels today, don’t try to transform everything at once. Start with the stage that offers the biggest opportunity or addresses the most pain.

Maybe that’s data entry, if you’re constantly dealing with incomplete addresses – stop the influx of more bad or deficient records that will need to be cleaned up. Maybe it’s database maintenance, if your decay rates are high. Maybe it’s return mail handling, if you’re not capturing and using ACS™ data effectively.

Improve one stage. Demonstrate results. Build momentum. Then expand to additional stages and work on integration.

The goal isn’t perfection. Remember, nothing is 100% in address quality. The goal is continuous improvement toward best practice levels, knowing that even best practice organizations still deal with undeliverable mail. They just deal with a lot less of it.

In the final article of this series, we’ll explore the fundamental truth that underlies all address quality work: nothing is 100%, and why that’s actually okay. We’ll discuss how to manage expectations, make decisions under uncertainty, and build resilient systems that work despite imperfect data.

For now, think about your organization’s address data quality lifecycle. Where are the weak points? Where are the biggest opportunities? That’s where to focus your attention and resources.

Because best practices aren’t about being perfect. They’re about being systematically better than the alternatives.

Next in this series

• The #1 Rule in Address Quality: Nothing is 100% (And Why That’s OK)

Want to go deeper on address data quality? Visit our Address Quality hub for tools, strategies, and real-world best practices.