An integrated audit evidence planning model to quantify the extent of audit evidence

Abstract

Audit evidence enables the auditor to express an opinion on the financial statements. To address the risk that the auditor may express an inappropriate opinion, the nature, timing and extent of audit procedures must be responsive to the assessed risks of material misstatement. The auditor must aggregate the levels of assurance obtained from different combinations of tests of controls, substantive analytical procedures and tests of details to respond to the assessed risks. These evidence planning decisions are complex and require professional judgement. Research has found that the extent of audit procedures is not linked to the assessed risks and that auditors may not know to aggregate evidence from different types of audit procedures. Research also supports the use of a structured audit methodology that includes decision models, to guide the application of professional judgement. This leads to the overall objective of this study: the development of an integrated audit evidence planning model to quantify the extent of audit evidence. The study employs a grounded theory model building approach, interpreting the relevant concepts and principles from the literature review into the development of the model. The integrated audit evidence planning model quantitatively relates the extent of audit evidence in a logical and structured manner with the risk assessment and three distinct overall levels of assurance needed to support the audit opinion. It uses the cumulative nature of audit evidence and the compensatory inter-relationship between tests of controls, substantive analytical procedures and tests of details to quantitatively aggregate the extent and levels of assurance from the different combinations of procedures to obtain reasonable assurance at the required overall level of assurance. The model provides a framework for influencing and guiding the exercise of professional judgement and is a practical and effective tool to benefit the users thereof when conducting an audit. Thus, the study models the extent of audit evidence with reference to the aggregation of different types and combinations of evidence and the linkage between the risk assessment and the extent of evidence that provides a flexible framework for the application of professional judgement regarding the gathering of audit evidence.