Audit firms are specialized companies that solely provide auditing services. These services not only include checking accounting records but also involve on-site inspections, investigations, analyses, and examinations of computational activities and all economic activities. Up to now, the number of professional companies in Beijing that engage in this type of auditing work is extremely limited.
As a form of supervisory mechanism, auditing has a long history in practice. However, there is no consensus among people regarding the definition of auditing. The definition widely recognized as representative and frequently cited is the one provided by the American Accounting Association in its 1972 publication of the "Statement of Basic Auditing Concepts," which defines auditing as "a systematic process of objectively obtaining and evaluating evidence about assertions concerning economic activities and events, and communicating the results to interested users."