Quality Rejection Rate
Quality Rejection Rate is the percentage of received, inspected, or produced units that fail defined quality acceptance criteria, calculated as rejected units divided by total units multiplied by 100. It can be reported as SQRR or PPM. Used at incoming inspection and supplier performance review to quantify raw material, component, or finished goods nonconformance.
In practice, quality rejection rate governs every gate before material enters production. Incoming inspectors compare delivered parts against the purchase order and inspection plan; any lot that exceeds acceptable reject levels is blocked and logged. That log drives supplier scorecards, quarantine decisions, and corrective action requests. When rejection rates climb, a plant is coping with stalled put-away, overburdened inspection stations, work order shortages, and expedite costs that inventory planners never sized. A shop-floor view is granular: rejection rate must be broken down by supplier, part number, lot, and inspection station so low lot rejection does not hide heavy defect density. The most effective operations pair the rate with root-cause codes such as dimension, contamination, labeling, packaging, or certificate mismatch. That combination turns a percentage into an actionable signal for accepting future shipments, adjusting sampling frequency, and deciding supplier approval.
How is Quality Rejection Rate different from defect rate?
Often used interchangeably, but some systems treat rejection rate as the proportion of units or lots rejected at acceptance, while defect rate may count all defective occurrences or defect opportunities. The exact definition must match the site's inspection logic.
Why use PPM instead of percent?
PPM is better for high-volume, low-defect supply chains because very small percentages are easier to compare as whole numbers; the same reject quantity can be expressed as Rejected Units ÷ Total Received Units × 1,000,000.
Should rejection rate be tracked per unit or per lot?
Both. Lot-based rejection measures how often shipments fail acceptance, while unit-based rejection measures how severe failures are inside failed lots; together they support more accurate supplier scoring and inventory risk assessment.