Dealing with each of the above in turn:
Audit software
Audit software is a generic term used to describe computer programs designed to carry out tests of control and/or substantive procedures. Such programs may be classified as:
Packaged programs
These consist of pre-prepared generalised programs used by auditors and are not ‘client specific’. They may be used to carry out numerous audit tasks, for example, to select a sample, either statistically or judgementally, during arithmetic calculations and checking for gaps in the processing of sequences.
Purpose written programs
These programs are usually ‘client specific ’ and may be used to carry out tests of control or substantive procedures. Audit software may be bought or developed, but in any event the audit firm’s audit plan should ensure that provision is made to ensure that specified programs are appropriate for a client’s system and the needs of the audit. Typically, they may be used to re-perform computerised control procedures (for example, cost of sales calculations) or perhaps to carry out an aged analysis of trade receivable (debtor) balances.