Internal Audit Sourcing Arrangement and the External Auditor's Reliance Decision

This paper examines the effects of internal audit sourcing arrangement on the external auditor's reliance decision in the presence of different levels of inherent risk and task subjectivity. We posit that external auditors will rely more on outsourced than in-house internal audit functions (IAFs) and that this difference will be more pronounced when inherent risk is high or when the work performed by internal auditors relates to a subjective task. Participants in the study were 127 external auditors from a Big 4 firm who completed an experimental case in which we manipulated internal audit sourcing, inherent risk, and task subjectivity. Results from the experiment indicate an interaction between sourcing and inherent risk such that external auditors rely more on outsourced than in-house internal auditors when the level of inherent risk is high but do not differentiate based on sourcing arrangement when inherent risk is low. While we find that reliance is lower for subjective than for objective tasks, we do not find an interaction between sourcing arrangement and the subjectivity of the work performed. We do find a marginally significant interaction between inherent risk and subjectivity of work performed: external auditors are less willing to rely on subjective work performed by internal auditors when inherent risk is high but do not differentiate based on task subjectivity when inherent risk is low. Additional analyses indicate that sourcing arrangement affects the reliance decision both directly and indirectly. The indirect effect appears to be mediated through external auditors' perceptions of internal auditor objectivity