Initially, the quality of a pharmaceutical product is determined by its design and science: a proven safety and efficacy of the active pharmaceutical ingredient (API) in its final formulation during the (pre)clinical development phase.

In the subsequent post-approval and commercial phase, a validated Good Manufacturing Practice manufacturing (GMP) process will yield the desired product consistently – batch after batch. During this phase there are various factors that can influence product quality beyond what is detectable by analytical testing of the finished product in the Quality Control laboratory.
Such factors include the quality of ingredients, the premises, the equipment, the hygiene standards, the temperature and cleanness of the environment, the production process and its documentation, in process controls, deviations from standard procedures, and the operators themselves.
Therefore, IDA subjects the physical facility and the entire manufacturing process together with the quality control procedures (sampling, inspection and analysis) to regular on-site auditing.