【正文】 稅收籌劃國(guó)際研討會(huì)論文集Using puter assisted verification in the detection of tax evasionPeter Best1．IntroductionSince 1986, Australia has had a ‘selfassessment’ taxation system, where taxpayers determine their own taxable ine, often with the assistance of a registered tax agent. Taxpayers prepare and submit their own taxation return. This, of course, raises the opportunity for ‘tax planning’, designed to minimise taxable ine, and the possibility of ‘tax evasion’, where the taxpayers deliberately lie to the Australian Taxation Office (ATO) about their activities to reduce their tax liability or fail to pay tax that is due.Taxpayers may evade tax by failing to declare assessable ine, claiming deductions for expenses that are fictitious or are not deductible, claiming input credits where goods and services tax (GST) has not been paid, treating domestic sales as export sales to avoid the requirement to remit GST on such sales, etc. Tax evasion is a serious concern since it results in the loss of government revenue which is intended to fund social services, health, and education, and gives taxpayers who evade tax an unfair advantage in the market and the munity.As a result, the Australian Taxation Office (ATO) has extensive audit processes to deal with these threats. Tax auditors conduct examinations of tax returns to detect failure to ply with the requirements of legislation. Taxpayers are selected for audit automatically based on the risk of tax evasion or error. A puterbased audit selection system scores taxpayer returns against thresholds and industry data, and highlights returns with greatest audit potential.When auditing a taxpayer’s return, the auditor may use manual procedures, such as physically examining documents. However, the ATO also uses Computer Assisted Verification (CAV) software to improve the efficiency and thoroughness of audits of returns.This paper examines the nature of tax auditing, the audit objectives which guide such audits, and the role played by CAV software in audits of tax returns. The application of CAV software is explained with reference to a case study.2．Nature of tax auditingAuditing may be defined generally as follows (Arens et al., 2007):Auditing is the accumulation and evaluation of evidence about information to determine and report on the degree of correspondence between the information and established criteria. Auditing should be performed by a petent, independent person. This definition of the auditing process is very broad. It applies to auditing of a pany’s financial statements as required by legislation. It also applies to audits of taxation returns. Some mon elements are present in each case.Information and established criteriaAudits involve the parison of information with criteria. The information may be the financial statements of a pany. The relevant criteria for the audit are international accounting standards. The auditor checks that the financial information has been prepared in accordance with those accounting standards.In taxation auditing, the information is the taxpayer’s ine tax return, and the criteria are the ine tax legislation – in Australia, the Ine Tax Assessment Act. In both types of auditing, the criteria for evaluating the financial information are very specific.Accumulating and evaluating evidenceEvidence is information collected and used by the auditor to determine whether the information is consistent with the relevant criteria. Evidence may include the examination of internal and external documents, inquiries of the auditee, calculations performed by the auditor, and examination of assets. Some evidence is more persuasive than others. Evidence obtained independently by the auditor is more persuasive than that oral responses to questions by management. The auditor should obtain sufficient appropriate evidence to support his/her conclusion on the information. This means a sufficient volume of evidence must be obtained, and it should be appropriate evidence. This is determined by the specific criteria. In auditing, these criteria normally take the form of a set of audit objectives, such as pleteness, accuracy, etc.Competent, independent personThe auditor must be petent and independent of the auditee. He/she must be qualified as an auditor and petent to know what and how much evidence is needed to reach the proper conclusion on the information. Being independent is very important for the audit conclusion to be credible. This means that the auditor should have no association with the auditee. In auditing of financial statements, an independent external auditor performs this task. Audits of taxation returns are performed by tax auditors employed by the Australian Taxation Office.ReportingReporting is when the auditor municates his/her conclusion on the information. The auditor’s report informs readers of the correspondence between the information and the criteria. In audits of financial statements, the auditor’s report is part of the pany’s annual report, distributed to investors and other stakeholders.Figure 1 summarises the important characteristics of auditing by illustrating an audit of an individual’s tax return by a tax auditor. The taxation return is examined to determine whether it meets the requirements of the Ine Tax Assessment Act. To acplish this, the auditor collects and examines sufficient, appropriate evidence. On pletion, the tax auditor issue an assessment showing taxable ine, taxation owing, taxation paid, and refund or amounts still to be paid.Figure 1 Audit of a Tax ReturnSource: Arens et al., 2007, p. 12.3．Assertions and audit objectives in taxation auditsAssertions are implied or expressed representations by taxpayers about the transactions included in a tax return. When a taxpayer prepares a tax return, he/she is asserting several things about the data included in the return.Five such assertions by taxpayers are:1． Occurrence In th