Acceptable Quality Level (AQL)

Acceptable Quality Level (AQL)

 The Acceptable Quality Level (AQL) is an industrial metric that determines the quality level of a good product or service that is the least tolerable. The acceptable quality level metric gives an insight into the number of items with defects that should be acceptable during evaluation or assessment.

If in the process of random evaluation of goods and services and it is discovered that the number of items with defects is below the acceptable quality level, it can be said that such good or service meets the acceptable quality level. However, if It is discovered that the number of items with defects exceeds the percentage of the acceptable quality level, it can be said that such a product does not comply with the acceptable quality level standard. This would require that all parameters, statistics and raw materials used during the production process be re-evaluated to know the origin of the defect.

The acceptable quality level is the level at which a product is considered to have the worst production standard. If a product has an AQL of 0.5%, it means that 99.5% of the entire production batch must be of a good standard. A product whose quality level is rejected is categorized as one that is always hazardous. The probability of a consumer accepting a product whose quality level is unacceptable is extremely low. A product whose quality level lies in a range between the acceptable quality level and the non-acceptable quality level has an indifference quality level and its AQL value varies with companies.

Understanding How the AQL works

This example below will give a better understanding of how the AQL works.

Dr. Meyer Industries deals in the manufacture of syringes and has an AQL value of 0.5% for each production round. This AQL of 0.5% means that not more than 0.5% of a production batch should be defective. If the company’s production batch is made up of 1,200 syringes, going by the AQL of 0.5%, it means that only 6 syringes should have any form of defect. If 7 syringes should have any defects, the entire production batch will be rejected.

The AQL varies between products and industries as well. It is believed that health products have a very strict AQL because damaged health products can result in health-associated risks. Products whose defects does not lead to health risk do not have strict AQL and are prone to getting spoilt.

AQL in relation to the types of defects

1.       Critical defects

Critical defects are defects that are unacceptable, and if accepted could become extremely hazardous. Critical defects often have an AQL level of 0%, any figure above 0% renders the entire production batch useless.

2.       Major defect

Major defects usually have an AQL of 2.5% and often, are not accepted by the final users.

3.       Minor defects

In this case, a product may have a defect; however, the defect does not affect its usability by the final consumer. Products with minor defects have an AQL of 4%.