감사법인특성과 감사시간․감사법인특성 결합효과의 감사품질 관련성

Advisory Committee on the Auditing Profession(ACAP)(2008) and International Organization of Securities Commission(IOSCO)(2009) suggested that it is necessary to develop audit quality indicators to be included in the transparency reports of the audit firms. It also presented possible examples of the audit quality indicators classified into input and output measures. Input measures include experience (including industry experience), competency, technical resources, employee workloads, and leverage (such as associate-to-partner ratios and the percentage of senior engagement team member time spent on an audit to the total audit time for all team members). Output measures include revenue information (such as revenues by service line [e.g., audit, tax, consulting, and other], geographic region, and industry), independence violation, disciplinary proceedings and legal matters. Bedard et al.(2010) categorized the audit quality indicators in terms of firm-level versus engagement-level indicators, as well as in terms of inputs and output measures, which are consistent with the quality control standards defined by ISQC 1 (International Standard on Quality Control No. 1)(International Auditing and Assurance Standards Board[IAASB] 2004). They argued that a single audit quality indicator is not a focus, rather they are to require reporting a number of different indicators so that the combination gives a multi-dimensional picture of audit quality. Researches related to audit quality in line with the argument include Hermanson et al.(2007) and Kim and Cheon(2010) which reported that, according to quality control investigations by U. S. Public Company Accounting Oversight Board (PCAOB) and the Financial Supervisory Service (FSS), certain audit firm characteristics related to human capital management could affect the auditors' quality control system, and, accordingly, are significantly associated with their audit quality. The above studies referred to various audit firm characteristics such as the associate-to-partner ratio, the professional staff-to-total employee ratio, and average involvement of partners or professional staffs per public company client. Based on these studies, I empirically tested what audit firm characteristics are significantly associated with the audit quality. Also, I see whether the average length of audit experience by the audit firms' professionals are associated with the audit quality. This is to examine controversy in Korea whether audit quality of large- and small-sized audit firms are different or not; ones argue that large firms have better quality while the others explain that their quality differences are not significant since small firms' professionals have longer experiences in average to compensate for the less organized firm. In addition, I note that the above audit firm characteristics are firm-level indicators as categorized by International Standard on Quality Control No 1.(ISQC 1)(IAASB 2004) and Bedard et al.(2010); I examined the combined effects of the firm-level indicators and (excess) audit hours on audit quality. Audit hour is an engagement-level indicator explained by Bedard et al. (2010) representing input of audit efforts in the engagement level. Prior period adjustments reported in the subsequent year were used as audit quality proxy. Samples are 1,584 firm-years of non-financial public companies listed in the Korea Stock Exchange with fiscal years ending December 31 from 2003 to 2009, which comprise of 503 firm-year of test samples (error firms) and 1,081 firm-year of control samples. I found that various audit firm characteristics are differently associated with audit quality; i.e. their significance and directions (positive or negative relationship) are not consistent. Specifically, variables representing auditor competency (average audit fees per partner) and audit firm's human capital leverage (the associate-to- partner ratio, the registered CPA-to-partner ratio, and the professional staff-to- total employee ratio) are significantly associated with good audit quality (i.e. lower prior period adjustments reported in the subsequent year). A variable representing auditor workloads (average non-audit fees per professionals) is significantly associated with bad audit quality. The numbers of public company clients per professional staff or partner do not have significant relationship with audit quality. In addition, the combined effects of the audit firm characteristics and excess audit hours are not consistent, either. Specifically, if the average number of listed company clients per professionals are larger, then incremental improvements in audit quality upon more excess audit hours become higher. However, if the audit firm's human capital leverages are higher, then the combined effects of the characteristics and excess audit hours made their aggregate audit quality improvements smaller. Similarly, if the average non-audit fees per partner is larger, then the combined effects of the characteristics and excess audit hours made their aggregate audit quality improvements smaller, too. These results indicate that various audit firm characteristics, and excess audit hours combined therewith, have different associations with the auditors' audit quality in terms of significance and directions (positive or negative relationship). Meanwhile, average length of audit experience of professionals belong to the auditors didn't show significant relationship with audit quality, but its combined effect with excess audit hours is significantly associated with good audit quality. This result also has regulatory implication because it negates the argument that small or medium-sized audit firms do not necessarily have worse audit quality because of length of audit experience are longer than those of large audit firms. This study's contribution is to find that various audit firm characteristics have different association with audit quality in terms of significance and directions. Specifically, I found that associate-to-partner ratio, a proxy for audit firm's human capital leverage, could be used as an audit quality indicator. Also, average length of audit experiences of the individual professionals who belong to the audit firms, is not associated with audit quality; rather its combined effects with excess audit hours representing the audit efforts in the engagement-levels only showed significant association with good audit quality.