The impact of the input level of information system audit on the audit quality: Korean evidence

In response to the increasingly sophisticated corporate information system environment in producing accounting data, audit firms are undertaking information system (IS) audit in addition to conventional auditing. This study focuses on examining the impact of input level of IS audit on audit quality. We collected data on IS audit hours, a unique reporting requirement for Korean listed-firms as disclosed in the External Audit Implementation Details beginning in 2014. Simultaneously, we used the amount of discretionary accruals and measure of conservatism, C_Score as the proxies of the audit quality. By empirically examining a sample set that includes 2,370 corporate-year observations from the Korea Composite Stock Price Index (2014–2018), we found that IS audit hours and IS audit personnel had a statistically significant negative correlation when estimating with amount of discretionary accruals using the model of Kothari et al. (2005) and positive correlation with C_Score. Even when the group was divided into Big 4 and non-BIG 4, these results were apparent in firm samples that were audited by Big 4 audit firms, whereas those audited by non-Big 4 firms did not show these results. Taken together, the following conclusion can be derived. Audit quality has improved through conducting IS audit in response to new types of audit risks that have emerged because of the use of information technology in corporations. Significantly, this study analyzes empirically the effect that the effort of IS auditing has on improving audit quality by using a unique reporting requirement for Korean-listed firms. The study confirms that an appropriate level of IS audit input can improve audit quality. In addition, it is meaningful that IS audit practice is following the risk-based approach of the Clarified International Standards on Auditing (ISA).