To ensure item production and system operation function at their best, businesses use quality control. Quality control monitors not only the product itself, but the way it is produced, stored and transported. Some quality control is voluntary, but sometimes quality control records must be kept for state and federal regulations. To make a product that is reliable and trustworthy, businesses use different types of quality control through every aspect of production.
When a company institutes protocol to check their system, this is called internal quality control. This can range from routine checking of equipment, having a co-worker go over another employee's data analysis, or running standards and controls on a regular basis. It is generally up to management to decide if internal quality control measures are reliable and performed as needed.
When products or data is sent to an outside business not affiliated with the company, this is external control. One example of external control is in food production. A food company may routinely analyze the nutritional value or shelf-life of a food item it produces in its own lab, but to verify its results, the food item will also be sent to an outside lab. This verification by an outside lab is important to obtain Food and Drug Administration (FDA) labeling and to prove to the FDA that the food company's production methods are sound.
A special type of quality control often done on a volunteer basis or to gain accreditation is proficiency testing. In this type of quality control, the company is sent a series of tests to perform. The results are sent back and the company receives a grade on its proficiency. This type of testing is often done in laboratories, where sensitive equipment and complex protocols need to be verified as accurate before the lab is allowed to continue its work.