There are two main levels of controlled shipping and some customers even require a third level. These are:
Controlled Shipping – Level 1 (CS1): CS1 requires the supplier to contain the suspect product and perform a redundant 100% inspection process. This process may be done by the supplier's employees, though some suppliers routinely employee an outside third-party inspection company to perform this service. Cost or availability of personnel is usually the driver for the decision whether to outsource this function or leave it in house.
The second step of CS1 is to identify the root cause of the defect and incorporate irreversible corrective actions. The third step of CS1 is to verify by the above inspection process that the corrective actions are effective