The origin of the review system goes back to the early beginnings of economic activity. Just as the economies have grown, the audit system has also further developed. Today IT-based audit processes are standard.

Revision can be distinguished in business and technical audit. The business audit (hereinafter referred to as revision) can be further broken down into external audit and internal audit. External auditors have a high degree of independence with a high degree of objectivity. Internal auditors do have a broad knowledge of internal processes and disciplinary actions involved with the management and are at least partially dependent.

External auditors acting at the request of management. The scope of each audit project is described in the audit engagement.