According to Shingo, what distinguishes an 'error' from a 'defect'?

Answer

A defect is an error that has reached the customer

Shingo clearly distinguished between an error, which is a deviation from the specified manufacturing process, and a defect, which is an error that has reached the customer.

According to Shingo, what distinguishes an 'error' from a 'defect'?
inventorManufacturingqualityprincipleerror proofing