Added Value of Auditing in a Non-Mandatory Environment

What is the 'raison d'etre' of auditing? Does auditing only exist by the grace of the legislator? Or does auditing fulfill other needs in contemporary society? For many companies, auditing has been made mandatory. This is possibly one of the reasons why researchers to date have given limited attention regarding the drivers for the demand for audit. Auditing (seen as a social control mechanism) is ...