No conscious effort in human society is divested of economic considerations and auditing is no exception. There is a growing realisation that the traditional approach to audit is economically wasteful because all efforts are directed to check all transactions without exception. This invariably leads to more emphasis on routine checking, which often is not necessary in view of the time and the cost involved.
With the shift in favour of formal internal controls in the management of affairs of organisations, the possibilities of routine errors and frauds have greatly diminished and auditors often find extensive routine checking as nothing more than a ritual because it seldom reveals anything material. Now the approach to audit and the extent of checking are undergoing a progressive change in favour of more
attention of the questions of principles and controls with a curtailment of non-consequential routine checking. By routine checking we traditionally think of extensive checking and vouching of all entries. The extent of the checking to be undertaken is primarily a matter of judgment of the auditor; there is nothing statutorily stated anywhere which specifies what work is to be done, how it is to be done and to
what extent. It is also not obligatory that the auditor must adopt the sampling technique. What he is to do is to express his opinion and become bound by that. To ensure good and reasonable standard of work, he should adopt standards and techniques that can
lead him to an informed professional opinion. On a consideration of this fact, it can be said that it is in the interest of the auditor that if he decides to form his opinion on the basis of a part checking, he should adopt standards and techniques which are widely followed and which have a recognised basis. Since statistical theory of sampling is based on a scientific law, it can be relied upon to a greater extent
than any arbitrary technique which lacks in basis and acceptability. The factors that should be considered for deciding upon the extent of checking on a sampling plan are following :
- Size of the organisation under audit.
- State of the internal control.
- Adequacy and reliability of books and records.
- Tolerable error range.
- Degree of the desired confidence.
It has already been pointed out that in most of the circumstances, the evidence available is not conclusive and the auditor always takes a calculated risk in giving his opinion. Even by undertaking hundred percent checking of the transactions, the auditor does not derive absolute satisfaction. This state of uneasiness led pragmatic auditors to adopt the statistical theory of sampling to derive the necessary satisfaction about the state of affairs by checking only a part of the total population of entries. Auditors realised that they can derive good satisfaction by undertaking a much lesser checking by adoption of this technique in the auditing process. It is a mathematical truth that the sample, if picked purely on a random basis would reveal the features and characteristics of the population.
By adopting the sampling technique, the auditor only checks a part of the whole mass of transactions. The satisfaction he used to derive earlier, by checking all the transactions, can be derived by a sample checking provided he can put reliance on the internal controls and checks within the clients organisation. Because they provide the reliability of the records, what should be the extent of desirable
checking in any particular matter is for auditor to judge on basis of his opinion about the state of control in a particular area. If control is satisfactory in its design and implementation, a much smaller sample can give the auditor the necessary reliability of the result he obtains. On the other hand, if in certain areas controls are slack or not properly implemented, the auditor may have to take a much larger
sample for getting satisfactory result. Another truth about the sampling technique should be noted. It can never bring complete reliability; it cannot give precisely accurate results. It is a process of estimation. It may have some error. What error is tolerable for a particular matter under examination is a matter of the individual’s judgment in that particular case. For example, Mr. X may consider that in his estimation of stores valuation, an error of 2% may not be material; he also decides that he needs at least 98% reliability of the result. He is to pick up the requisite number of items of the stores for reliability of the result. The requisite number he can get from the random number table. The question of reliability of the result is directly linked with the reliability of the internal control and of the books and records; when these are satisfactory, lesser degree of reliability of the sampling estimation may suffice — if these are not satisfactory, the auditor may have to decide upon a higher degree of reliability which can only be obtained from a larger sample.