Quality Control Inspectors may use a variety of methods to test the goods they inspect. These methods can include visual inspections, measuring and gauging, testing and inspection equipment, and non-destructive testing. Additionally, Quality Control Inspectors may also employ special techniques such as sampling and statistical analysis to ensure that the quality of the goods meets the required standards.  

The method of inspection used by a Quality Control Inspector will vary depending on the goods being inspected. Visual inspection is often used for goods with visible characteristics such as surface defects and incorrect dimensions. For goods with invisible characteristics, such as electrical components, testing, and inspection equipment may be used to measure and verify properties. Non-destructive testing may also be employed to detect certain problems.

The sample quantity for both visual and functional inspection will depend on the product and the standards set by the Quality Control Inspector. Generally speaking, visual inspection of products should cover all sample pieces, while functional inspection may require fewer pieces depending on the complexity of the product.