The primary advantage of using internal control questionnaires (ICQs) as part of a preliminary survey for an engagement is their efficiency. ICQs allow auditors to quickly gather a large amount of information about the control environment by asking structured questions that cover key areas of interest. This helps in identifying areas that require further investigation or where controls may need improvement.
IIA References:
* The IIA's Practice Guide on Evaluating Internal Controls mentions that ICQs are useful for obtaining an initial understanding of controls and are particularly efficient when time or resources are limited. They allow auditors to systematically cover a wide range of control-related topics in a relatively short period.