5 Discussion and conclusions
In this study, we examined determinants of external auditors’ reliance on internal audit work and evaluated the impact of three environmental factors in the relationship between internal and external auditors. In particular, we investigated the infuence of client business risk, the efectiveness of the internal control system, and the quality of corporate governance on the willingness of external auditors to rely on the IAF. Also, the efect of the type of audit procedure and the inherent risk of the examined transaction on the reliance decision was investigated. Moreover, we examined the interactions between the determinants and analysed the infuence of past experiences with an IAF on the extent of external auditor reliance on the IAF, measured by the previous intensity of collaboration and the way of communicating with an IAF. Taking prior willingness to cooperate and communicate into consideration introduces new aspects to this research topic.
Consistent with regulatory guidance and previous studies, external auditors exhibit a willingness to place some degree of reliance on their client’s internal audit work. The results of our study suggest that external auditors’ reliance decision is impacted by difering levels of the three main factors. We demonstrate that external auditors may place a higher degree of reliance on the IAF, if the business risk of the audited company is lower, the internal controls are more efcient, or the quality of corporate governance is higher. Thus, our fndings indicate that external auditors perform in accordance with ISA 610.18, i.e. their reliance on the IAF decreases with an increasing risk of material misstatements. Furthermore, we identifed an interaction between the efectiveness of internal controls and the quality of corporate governance, in that strong internal controls might compensate for weaknesses in corporate governance with respect to the confdence of external auditors in the work of the IAF. Especially the efectiveness of the internal control system and the quality of corporate governance are criteria that can be infuenced and regulated by the management of a company.