Audits are performed to evaluate the validity of information and assess internal controls. The goal is to express an opinion on the system or organization being audited based on testing. There are two basic types of audits: financial audits review accounting and financial reporting, while non-financial audits check compliance and customer satisfaction. Audits can also be statutory, private, internal, for management, or of information systems. The audit process typically involves planning, fieldwork, reporting, and follow-up to constructively improve the organization.