Amazon's order defect rate is caused by the seller's orders leading to buyers filing returns, refunds, negative reviews, or complaints to Amazon.

These defects include failure to ship on time, order cancellations, shipments not as described, delayed shipments, lost or damaged packages, buyers not receiving items, returns not made as requested by customers, failure to provide valid tracking information, failure to address buyer issues, long order processing times, product quality issues, false advertising, sellers violating Amazon policies, etc.

Amazon evaluates sellers' performance based on their order defect rate, and may result in the suspension or closure of sellers' accounts.