答案:
(a)Advantages and disadvantages
(i) Analytical procedures
Advantages
1.The main advantage of analytical procedures is that they can be used at all stages of the audit to enquire into the absolute amounts to be included in the financial statements, and into the relationships between those amounts.
2.Analytical procedures are a good test for the overall reasonableness of an amount. They can be used on a global basis, and they can be split down into their constituent elements.
3. Analytical, procedures enable the auditor to make comparisons on a continuous basis, taking prior years into account, and providing the auditor with a better understanding of both the business as a whole, and of individual account areas.
Disadvantages
1.Analytical procedures often have to be performed on management accounts, or draft or incomplete accounts before the final financial statements have been prepared. This means that significant adjustments, which are often made at a late stage, are not taken into account.
2. Without a prior and proper understanding of the business, the auditor may be tempted to accept the results of analytical procedures that show no unusual variations as evidence that there is nothing wrong, which may not be the case if there have been significant changes in the business of which the auditor is unaware (and which management may wish to hide from the auditors).
3. Auditors may also be tempted to accept ‘plausible’ explanations for changes and variations without much further substantiation, where further investigation may actually be warranted.
(ii) Audit sampling
Advantages
1. Audit sampling enables the auditor to draw conclusions about a population without testing all of the transactions or balances in the population as a whole.
2. Audit sampling also enables the auditor to concentrate on high risk or high value items, and to differentiate between elements of a population which may be subject to differing internal controls.
Disadvantages
1. There is always a risk that the auditor’s sample is not representative of the population as a whole (known as ‘sampling risk’). Auditors calculate and accept this risk, and perform other procedures to compensate for it, but it always remains a risk.
2. Sampling relies on the use of judgement in relation to materiality, exceptions, and in drawing conclusions, for example. Judgement can be abused, or simply fail, particularly where staff are inexperienced.
(iii) Tests of controls
Advantages
1. Tests of controls enable the auditor to establish whether a control system in operation is effective. If properly designed controls are operating as prescribed, auditors can reduce the level of substantive testing required at the period-end.
2. Tests of controls mean that auditors do not have to concentrate all of their efforts on substantive procedures at the period-end which would in many cases be impractical, inefficient and not cost-effective.
Disadvantages
1. Tests of controls are often performed on a sample basis (disadvantages noted above).
2. Tests of controls are often performed on routine transactions for which there are high quality automated controls. The very high risk areas in financial statements are often outside this area and relate to non-routine transactions and more intangible environmental or general controls which are not easy to test.
(iv) Detailed testing of transactions and balances
Advantages
1. In detailed testing of transactions and balances, auditors are directly examining the figures figures and assertions that appear in the financial statements.
2. Detailed testing enables the auditors to form a view to whether the figures on which he is reporting are fairly stated and often involves third party, written confirmation which is a good source of audit evidence.
Disadvantages
1. Detailed testing of transactions and balances is often performed on a sample basis (disadvantages noted above).
2. The level of testing of transactions and balances is determined by the level of comfort obtained by the auditor from tests of controls. If too much comfort has been obtained from tests of controls, it is likely that any error will be compounded by an inadequate level of testing of transactions and balances.
(v) Computer assisted audit techniques (CAATs)
Advantages
1. CAATs enable the auditors to test a large volume of data, or the operation of the controls in a system, accurately and quickly. They are therefore very-cost efficient when operated properly.
2.CAATs reduce the level of human error in testing and enable a very high level of audit evidence to be derived.
3. The use of CAATs frees up expensive human resources that would otherwise be engaged in routine, mechanical work to concentrate on judgemental areas.
Disadvantages
1. CAATs are expensive to set up and require the co-operation of the client. It is usually necessary for a continuing audit relationship to be present before it is worth committing the audit resources.
2.Major changes in client systems often require major changes in CAATs, which is expensive. If the audit fee is based on the assumption that the prior year’s CAATs can be used, and a change is made without warning, the client may have unrealistic expectations about the level of service that can be provided for the fee.
(b) Relationship between the methods of evidence gathering
(i) Analytical procedures are often first used during the planning stage of the audit. Materiality levels and levels of tolerable error are often derived (at least in part) from analytical procedures. These are in turn used in audit sampling procedures.
(ii) Analytical procedures help the auditor determine the audit approach (the levels and areas for tests of controls and detailed testing).
(iii) The results of tests of controls determine the level of detailed testing of transactions and balances. Analytical procedures provide indirect evidence as to the effective operation of internal controls (if controls are working, analytical procedures may help prove that the population as a whole is fairly stated).
(iv) Detailed tests of transactions and balances are often performed towards the end of the audit in conjunction with analytical procedures-analytical procedures compensate to an extent for the weaknesses in sampling procedures both for tests of controls and detailed testing of transactions and balances (and vice versa).
(v) Sampling is used for both tests of controls and detailed testing of transactions and balances. Where CAATs are used, sampling may not be necessary because CAATs can often be used to the whole population, either for tests of controls, or for detailed testing of transactions and balances.