The primary purpose of this dissertation is to investigate the influence of the auditor's locus of control on auditor judgement in the context of a complex auditing task, going concern evaluation. Other objectives involve examining the influence of information type and decision aid availability (and their interaction with each other and with locus of control) on this task. In examining the influence of locus of control on going concern assessment, the study makes a significant original contribution to the extant literature in audit judgement.  Despite the exploratory nature of the study, the findings indicate differences in the decision making behaviour of individuals with an internal locus of control (internals) versus those with an external locus of control (externals), particularly with respect to perceived information relevance. Decision aids were found to influence perceptions of information relevance or task complexity on controlling for locus of control. Internals did not display greater decision accuracy than externals. Evidence of the dilution effect was found on controlling for locus of control. Information type, decision aid availability, and locus of control interacted to influence decision accuracy. Overall, the results indicate that internals, achieve better decision performance than externals if they are unaided, or if they have access to a decision aid in mixed information environments. The results also suggest that auditors' professional judgement is an important factor influencing decision performance.