Why your mailing list is the most important part of your campaign
Direct mail experts say the list accounts for up to 40% of your campaign's success. We make sure yours is working for you, not against you.
Undeliverable mail costs you twice
Every undeliverable piece costs you the print cost, postage, and the missed opportunity cost of a prospect you paid to reach but never did. NCOA and CASS processing eliminates most of that waste before your job enters production.
Deliverability directly affects ROI
Industry data shows that list quality accounts for 40% of a direct mail campaign's performance — more than creative, offer, or format. A 10% improvement in deliverability on a 20,000-piece campaign means 2,000 additional impressions at zero extra cost.
Better targeting multiplies response rates
Mailing to an unfiltered purchased list might yield 0.3–0.5% response. A properly segmented list targeted by income, life event, or behavioral trigger routinely outperforms by 3–6× in the same vertical. Targeting is the highest-leverage variable you control.
USPS compliance is non-negotiable
USPS automation postage rates — which save 30–35% versus single-piece rates — require CASS-certified, presorted mail. Without compliant data, you pay full price. We keep your lists USPS-compliant on every campaign.
Our data services: NCOA, CASS, deduplication, and list acquisition
NCOA Processing (National Change of Address)
Every year, roughly 35 million Americans move. NCOA processing updates your list with current addresses from the USPS national database, so you're mailing to where people actually live — not where they lived 18 months ago. Required for USPS automation postage rates.
Deduplication & Merge/Purge
We identify and eliminate duplicate records at the individual, household, and business level — including fuzzy-match duplicates where names are spelled differently. Most unprocessed lists contain 5–12% duplicates. We cut that to near zero before your job goes to press.
Targeted List Acquisition
We source consumer and B2B mailing lists filtered by geography (ZIP code, county, radius), age, household income, home value, homeownership, presence of children, purchase behavior, business SIC code, employee count, and hundreds of other demographic and firmographic selects.
Consumer & Business List Access
Access to more than 245 million verified consumer records and 14 million US businesses, updated continuously from credit bureaus, public records, and opt-in sources. We pull list counts and demographic breakdowns before you commit, so you can size your campaign with confidence.
CASS & DPV Address Certification
CASS (Coding Accuracy Support System) standardizes your addresses against official USPS databases and assigns Delivery Point Validation codes. The result: cleaner addresses, fewer undeliverables, and qualification for automation presort discounts that reduce your postage cost by up to 35%.
List Analytics & Campaign Planning
Before purchasing any list, we pull preliminary counts and demographic breakdowns segmented by your target criteria. This lets you see exactly how many records are available, plan your quantity, and refine your targeting — before spending a dollar on printing or postage.
List Hygiene — NCOA, CASS, and Deduplication Explained
List hygiene is the process of cleaning and correcting a mailing list so that every record points to a real, current, deliverable address — and it is the single most cost-effective step in any direct mail campaign. Roughly 35 to 40 million Americans change their address each year, which means an unprocessed list decays at a rate of about 1% per month. After 18 months without updating, a typical list will have 12–18% of its records pointing at the wrong address. Every undeliverable piece costs you the full print and postage spend plus the opportunity cost of a prospect you paid to reach but never did.
NCOA (National Change of Address) processing is the core of list hygiene. We run your list against the USPS NCOA database, which contains every change-of-address filing from the past 48 months. When a match is found, the old address is replaced with the new one — so mail that would have been forwarded or returned instead reaches the recipient at their current location. NCOA also flags records that have moved with no forwarding address, allowing you to suppress them before printing. This step is required to qualify for USPS automation postage rates, which can reduce postage by 30–35% versus single-piece rates.
CASS (Coding Accuracy Support System) certification standardizes every address to the official USPS format, assigns ZIP+4 codes, and applies Delivery Point Validation (DPV) to confirm the address is a real, deliverable point. Deduplication and merge/purge remove duplicate records at the individual, household, and address level — including near-matches where names are spelled differently or abbreviated. Most unprocessed lists carry 5–12% duplicates, which means you are paying to mail the same person twice. We cut that to near zero before press. Together, NCOA, CASS, and deduplication form a hygiene regimen that maximizes deliverability, qualifies your mail for the lowest postage rates, and eliminates the waste that silently erodes campaign ROI.
List Acquisition and Targeting Selects
When you do not have an existing list — or when you need to reach new prospects — Dimaco sources targeted consumer and business mailing lists filtered to match your ideal customer profile. Our data partners provide access to more than 245 million verified consumer records and 14 million US business records, updated continuously from credit bureaus, public records, and opt-in sources. Before you commit to a purchase, we pull preliminary counts and demographic breakdowns so you can see exactly how many records are available and plan your quantity with confidence.
Consumer lists can be filtered by hundreds of selects. Geographic selects include ZIP code, carrier route, county, and radius around an address. Demographic selects include age, household income, home value, homeownership status, presence and age of children, education level, occupation, and marital status. Behavioral and life-event selects capture the moments when consumers are most likely to buy: new movers, new homeowners, recent refinancers, new parents, and households with recent credit inquiries. For Medicare and insurance campaigns, age-based selects (such as turning 65 within a defined window) timed to open enrollment are among the highest-converting lists available.
Business-to-business lists are selected by SIC or NAICS industry code, employee count, annual revenue, years in business, location type (single location vs headquarters), and job title of the decision-maker. A B2B campaign targeting office managers at dental practices with 5–20 employees is a very different list from one targeting CFOs at mid-market manufacturers, and the right selects determine whether your piece reaches the person who can say yes. We also build suppression files — removing existing customers, competitors, or Do-Not-Mail registrants — so you never pay to mail someone who should not receive your message. Every list we source is NCOA-processed and CASS-certified before it goes to press.
Data Security Practices for Mailing List Processing
Mailing lists often contain personally identifiable information — names, addresses, and sometimes phone numbers or account references — and protecting that data is both a legal obligation and a matter of client trust. Dimaco treats every list as confidential by default. Lists are transmitted through our secure file transfer portal rather than over email, stored on access-controlled internal systems, and processed only by authorized production staff. We do not share, resell, or repurpose client data, and lists are retained only as long as needed for production, reprint, or audit purposes.
For clients in regulated industries — healthcare, insurance, financial services — we follow HIPAA-aware data handling practices. This includes limiting access to patient and policyholder lists to the minimum number of staff required for production, processing variable data fields with documented workflows, and ensuring that any merge between client data and our internal systems is logged. When a campaign requires matching a client file against an external list (for example, suppressing existing customers from a prospect list), the match is performed in a controlled environment and the output is reviewed before press.
Data destruction is handled with the same discipline as processing. When a list is no longer needed, files are securely deleted from production systems, and any physical printouts or proofs are shredded. We can accommodate client-specific data security requirements — including signed business associate agreements, custom data retention windows, and dedicated processing environments for sensitive campaigns. If your organization has specific compliance, privacy, or data governance requirements, our team will work with your IT, legal, or compliance group to meet them before any data is accepted for processing.