A survey conducted by the International Forum of Independent Audit Regulators (IFIAR) found that many audits still have significant areas of deficiency, primarily relating to fair value measurement, internal controls testing, and disclosure adequacy. IFIAR members inspected audits at public companies and large financial institutions using the six largest accounting firms (including the Big Four). In many cases, the inspections indicated that the audit firm did not gather enough evidence to support its audit opinion. Among the public companies reviewed, the leading area of deficiency was fair value measurement, which arose in 17% of cases.