ASN Best Practices: How to Prevent Advance Shipping Notice Failures

ASN failures are the single most common source of retail chargebacks that we see when onboarding new clients from other 3PLs. The reason is structural: unlike labeling errors or packaging violations, which are visible on the warehouse floor, ASN errors are invisible until the retailer's system flags them. A shipment can look perfect—correct products, proper labeling, on-time delivery—and still generate a chargeback because the electronic notification did not match the physical reality.

The good news is that ASN failures are almost entirely preventable. They are configuration problems, not ongoing operational problems. Once the EDI system is correctly configured to generate accurate ASNs from actual shipment data, and automated validation catches any exceptions before transmission, ASN chargebacks drop to near-zero. The challenge is getting that configuration right during setup—and that requires understanding exactly where ASN errors come from.

What an ASN Contains and Why It Matters

An Advance Shipping Notice (EDI 856) is a structured electronic document that tells the retailer exactly what is on its way. At minimum, an ASN includes the purchase order reference, a list of items being shipped with quantities, the SSCC-18 identifiers for each pallet and carton, carrier and tracking information, and the expected delivery date.

Retailers use the ASN for three purposes. First, receiving planning: knowing what is arriving allows the DC to schedule labor and dock space. Second, scan-based receiving: when a pallet arrives, the DC scans the SSCC-18 barcode and the system looks up the ASN to verify contents without opening every carton. Third, inventory management: the ASN feeds into the retailer's inventory system so that incoming stock is accounted for before it is physically put away.

When the ASN does not match the shipment, all three purposes break down. Receiving takes longer because discrepancies must be resolved manually. Scan-based receiving fails because the system cannot match the physical pallet to the electronic record. And inventory accuracy suffers because the system expected one thing and received another. This is why retailers penalize ASN errors aggressively—inaccurate ASNs disrupt their entire distribution center operation.

The Five Categories of ASN Failure

After two decades of setting up retail compliance for brands shipping to 60+ retailers, we have categorized ASN failures into five types. Each has a distinct root cause and a specific fix.

1. Quantity Mismatches

The ASN reports a different quantity than what was physically shipped. This is the most common ASN failure and almost always has the same cause: the ASN was generated from the purchase order quantity instead of the actual pick-and-pack quantity.

Purchase orders request specific quantities, but the actual shipment may differ—short picks due to inventory discrepancies, damaged units removed during packing, or partial fills approved by the retailer. If the ASN pulls from PO data rather than WMS shipment confirmation data, every partial shipment generates an ASN mismatch.

The fix: Generate ASNs from actual pick-and-pack records, never from PO quantities. The ASN must reflect what was loaded onto the truck, not what was ordered.

2. Timing Violations

The ASN was transmitted outside the retailer's required window. Most retailers require the ASN to be sent after the shipment physically departs the facility and before it arrives at the DC. Sending the ASN before departure risks transmitting data for a shipment that has not actually left (and might be modified before it does). Sending it after arrival means the DC received cargo with no advance notification.

The fix: Automate ASN transmission to trigger on carrier pickup confirmation. When the carrier scans the shipment as picked up, the system immediately transmits the ASN. This guarantees the shipment has departed and provides maximum advance notice.

3. SSCC Correlation Errors

The SSCC-18 numbers on the physical labels do not match the SSCC-18 numbers in the ASN. This creates a fundamental problem at receiving: the DC scans a pallet barcode but the system cannot find a matching record in the ASN. The pallet must be processed manually, and a chargeback is issued.

SSCC mismatches happen when labels are reprinted without updating the ASN, when labels and ASNs are generated from different data sources, or when label generation and ASN generation run at different times with different data snapshots.

The fix: Generate labels and ASN data from the same source, at the same time, in a single workflow. The label generation process should produce both the physical label and the corresponding ASN line simultaneously, guaranteeing a one-to-one match.

4. PO Reference Errors

The ASN references the wrong purchase order number, uses an incorrect format for the PO reference, or maps to the wrong PO type. These errors are particularly common when a retailer uses multiple PO formats—standard replenishment, promotional, seasonal, or different formats for different business units.

A configuration that correctly handles standard replenishment POs may not correctly handle promotional POs if they use different reference number structures. The system works fine for months on replenishment orders, then the first promotional PO comes through and generates an ASN failure.

The fix: During onboarding, map every PO format the retailer may issue. Configure and test ASN generation for each format. Do not go live until all PO types produce correct ASNs in testing.

5. Format and Field Errors

The ASN contains the correct data but in the wrong format. Each retailer has specific EDI formatting requirements—field lengths, data types, segment ordering, and qualifier codes. An ASN that validates against one retailer's specifications may fail against another's because of formatting differences that are invisible at a data level.

The fix: Use retailer-specific EDI maps that encode each retailer's exact formatting requirements. We maintain these through SPS Commerce, which provides pre-built maps for 60+ retailers.

To illustrate how seriously retailers treat ASN accuracy: Walmart's SQEP program dedicates its entire Phase 1 enforcement to PO and ASN accuracy defects—overages, shipments against canceled POs or lines, items not on the PO, wrong pack configurations, missing ASNs, erroneous ASN data, and late ASN submissions. Each of these is a distinct defect category with its own chargeback. Target tracks ASN accuracy as a separate compliance metric on their vendor scorecard, measured independently from on-time delivery and in-full quantity. The common thread across retailers: ASN errors are almost always configuration problems, not one-time mistakes. Once you fix the root cause, the errors stop on every subsequent shipment.

Building an ASN Validation System

Prevention is better than correction. Here is the automated validation system we use to catch ASN errors before they reach the retailer.

Pre-Transmission Validation

Before any ASN is transmitted, the system runs automated checks against five criteria: quantities match WMS shipment confirmation, SSCCs match generated labels, PO references are valid and correctly formatted, the shipment has departed (carrier pickup confirmed), and the ASN format conforms to the specific retailer's EDI specifications. Any validation failure holds the ASN for review rather than transmitting incorrect data.

Exception Handling

When validation catches an error, the system routes it for immediate resolution. Quantity mismatches trigger a review of the pick record. SSCC errors flag a label verification. PO reference issues escalate to the EDI configuration team. The goal is resolution within minutes, not hours—because the ASN still needs to be transmitted before the shipment arrives.

Post-Transmission Monitoring

After transmission, monitor for retailer acknowledgments (EDI 997 functional acknowledgments). A rejected ASN is an immediate signal that something failed validation on the retailer's end. Track rejection rates by retailer and by error type to identify configuration issues that the pre-transmission validation may not catch.

Integration speed directly affects ASN accuracy because the longer the setup takes, the more shipments go out with untested configurations. A provider with pre-established retailer connections can move from onboarding to validated ASN transmission in weeks rather than months—which means fewer shipments exposed to configuration errors.

ASN Accuracy at Scale

ASN processes that work at low volume can break at scale. During peak seasons when shipment volume doubles or triples, the same validation checks run against many more transactions. System performance, processing queue capacity, and transmission timing all face pressure.

The brands that maintain ASN accuracy through peaks do so because their validation is automated and built into the workflow rather than dependent on manual review. Manual ASN verification might catch errors at 50 shipments per day. At 200 shipments per day, manual review becomes a bottleneck that either slows the operation or gets bypassed—and bypassed validation means undetected errors.

We build ASN validation into the standard fulfillment workflow so that it runs automatically regardless of volume. The system validates every ASN against every check, every time. At 50 shipments or 500, the validation is the same.

We are hitting all the SLAs over and over again. Productiv has led the charge and brought so many improvements to the table over the last two years. There's nothing glaring that stands out anymore and now we are just fine tuning.

If ASN failures are a recurring problem in your retail operations, the issue is almost certainly in the configuration—not in the people running the warehouse. Fixing it requires mapping every failure mode, building automated validation for each one, and testing against every PO type and retailer your business touches. Start a conversation with our team and we can walk through your current ASN setup to identify where the gaps are.