Audit Opinion

An auditor's opinion is a certification that accompanies financial statements based on an audit of the accountant's opinion of the procedures and records used to produce the statements regardless of whether material misstatements exist in the financial statements. There are generally four types of audit opinions rendered in accounting.

Unqualified Opinion

An unqualified opinion is also call as a clean opinion. An unqualified opinion is an audit report that is issued when an auditor determines that each of the financial records provided by the organization is free of any misrepresentations. In addition, an unqualified opinion indicates that the financial records have been maintained in accordance with the standards known as Generally Accepted Accounting Principles (GAAP). This is the best type of report a business can receive. Typically, an unqualified report consists of a title that includes the word “independent.” This is done to illustrate that it was prepared by an unbiased third party.

Qualified Opinion

A qualified opinion is given when a company’s financial records have not been presented in accordance with GAAP but no misrepresentations are identified, an auditor will issue a qualified opinion. The writing of a qualified opinion is extremely similar to that of an unqualified opinion. A qualified opinion, however, will include an additional paragraph that highlights the reason why the audit report is not unqualified. 

Disclaimer Opinion

On some situation, an auditor is unable to complete an accurate audit report because of a variety of reasons, such as an absence of appropriate financial records. When this happens, the auditor issues a disclaimer of opinion, stating that an opinion of the firm’s financial status could not be determined.  A disclaimer of opinion is not an opinion itself. 

Adverse Opinion

A disclaimer of opinion means that due to a significant scope limitation, the auditors were unable to form an opinion or did not form an opinion on the financial statements. An adverse opinion indicates financial records are not in accordance to GAAP and are grossly misstated. An adverse opinion is an indicator of fraud, and public entities that receive an adverse opinion are forced to correct their financial statements and have the financial statements re-audited. 

References
http://yourbusiness.azcentral.com/types-audit-opinions-rendered-accounting-3557.html
http://www.investopedia.com/terms/a/auditors-opinion.asp