An opinion is not a guarantee of an outcome, but rather a statement of professional judgement. The auditor cannot obtain absolute assurance that financial statements are free from material misstatement because of the inherent limitations of an audit. These are caused by a number of factors. For example, many financial statement items involve subjective decisions or a degree of uncertainty (e.g., accounting estimates). Consequently, such items are subject to an inherent level of uncertainty which cannot be eliminated by the application of auditing procedures.