IRDR (Inventory Record Defect Ratio)

Amazon & D2C glossary · Harpy Media

IRDR (Inventory Record Defect Ratio) measures how far Amazon’s system records diverge from physical reality: the share of units where what the system expects doesn’t match what’s actually on the shelf. It’s the accuracy score of your inventory footprint inside the network.

What is IRDR?

IRDR (Inventory Record Defect Ratio) measures how far Amazon’s system records diverge from physical reality: the share of units where what the system expects doesn’t match what’s actually on the shelf. It’s the accuracy score of your inventory footprint inside the network.

IRDR is an internal-quality metric with external teeth: when the ratio climbs past its threshold, Amazon starts trusting your inventory records less — triggering investigations, reduced confidence in your data (which affects how the system plans your replenishment), and potentially operational or financial consequences. The causes are exactly the ones the rest of the inbound stack works to prevent — miscounts at check-in, mislabels, damage, shrinkage, and inaccurate shipment declarations — arriving as a single number.

What drives the ratio up

The contributing causes, ranked by how often sellers actually meet them: shipment-declaration mismatches (what you said you sent versus what arrived — carton counts, hierarchy data, ASN accuracy: the same discipline chain from the IPIP/IPMP and D2FC entries), check-in mis-scans (labels that fail, units that confuse the scanner), damage and loss between dock and shelf (packaging that doesn’t survive the network), and the ordinary entropy of returns and disposals not yet reconciled. Because it’s a ratio across all your units, the fix isn’t one dramatic repair — it’s pulling down the frequency of small errors everywhere: accurate declarations, surviving packaging, and reconciled discrepancies. The sellers with strong IRDR are simply the ones whose upstream processes stopped generating defects.

Keeping the ratio healthy (the routine)

Three habits. Reconcile regularly — the inventory ledger review (monthly) surfaces discrepancies while they’re small enough to correct cheaply; unexplained deltas left to accumulate become the ratio’s raw material. Declare precisely — every shipment ships with data that matches its physical contents (counts verified, hierarchy current, ASN transmitted and accurate), because the declaration is what the system compares reality against. And protect the physical — packaging engineered for the journey (damage = discrepancy) and label specs enforced at origin (scan failures = discrepancy). For vendors and sellers in programmes where inventory accuracy feeds performance scoring, IRDR is worth watching as a leading indicator, not just a consequences trigger: by the time it breaches a threshold, the upstream causes have been compounding for a while.

In practice

A vendor’s IRDR trends upward across two quarters, with discrepancy investigations multiplying. The pattern analysis lands on the familiar culprit with a twist: their new freight lane uses consolidation transloading where cartons get re-stacked — and cheap cartons are arriving with crush damage in the middle layers, units physically lost to damage but declared and expected by the system. Thicker board spec on the two affected carton sizes and a damage-report review routine later, discrepancies fall back toward baseline. The ratio was the messenger; the cartons were the message.

How Harpy Media helps

Inventory-accuracy management — declaration discipline, packaging survival, and reconciliation routines — is part of how we keep vendor records trusted at scale.

IRDR FAQ

What is IRDR?

Inventory Record Defect Ratio — the percentage of units where Amazon’s system records and physical inventory disagree; an accuracy KPI with consequences at threshold.

What causes high IRDR?

Inaccurate shipment declarations, mis-scanned labels, transit damage, shrinkage, and unreconciled discrepancies — upstream process defects showing up as an accuracy score.

How do I improve it?

Declare shipments precisely (counts/hierarchy/ASN accurate), enforce label and packaging survival specs, reconcile the ledger routinely, and trace every discrepancy to its cause.