本研究探討產業專家對審計品質的影響。根據以往文獻使用會計師事務所產業佔有率衡量產業專家變數。本研究首先跟先前研究相同使用橫斷面迴歸模型探討產業專家對審計品質的影響,結果與先前研究一致,產業專家與裁決性應計數絕對值呈顯著負相關,表示產業專家有較佳的審計品質。 本研究使用規模與傾向分數兩種方法配對產業專家與非產業專家變數,以降低選擇性偏差與客戶規模特性問題。使用規模就產業專家與非產業專家配對後之結果顯示,產業專家與裁決性應計數絕對值依然呈顯著負相關,但顯著性較全樣本結果不顯著。再以傾向分數配對後之結果顯示,產業專家與裁決性應計數絕對值呈負相關但並不達顯著水準。因此,這個研究結果表示,在衡量會計師產業專業化時,使用市場佔有率來衡量,並不是一個可靠的指標。儘管如此,研究結果表示使用市場佔有率來代替產業專家變數會導致模型偏差,但這並不表示產業知識對會計師事務所是不重要的,而是提供往後產業專家領域之研究針對探產業專家衡量方法提出更精確之方法,使其衡量較無偏差。
This study examines whether auditor industry specialization, measured using the auditor’s within-industry market share, improves audit quality proxied by the magnitude of absolute discretionary accruals. The full sample results run by cross-sectional regression model are consistent with prior literature that auditor industry specialization is positively associated with audit quality. To mitigate model misspecification problems by reducing or even eliminating the correlation between the treatment variable and the matching variables, the main analyses of this study, for audit-quality proxy and specialization measure, clients of specialist and nonspecialist auditors are matched using both client size and propensity scores. After matching clients of specialist and nonspecialist auditors on client size, the results show that industry specialization is positively associated with audit quality. The results are the same as that of the full sample, whereas the significant level is lower than that of industry specialization is positively associated with audit quality. After matching clients of specialist and nonspecialist auditors on propensity scores, the evidence shows that the association industry specialization is positively but statistically insignificant associated with audit quality. The combined evidence in this study suggests that the auditor’s within-industry market share is not a reliable indicator of audit quality. Nevertheless, these findings do not imply that industry knowledge is not important for auditors, but that the methodology used in extant archival studies to examine this issue does not fully parse out the effects of auditor industry specialization from client characteristics.