關鍵查核事項是否顯示查核風險

審計準則公報第五十八號自2016年起，要求查核報告揭露查核過程發現的最重要事項，此關鍵查核事項應使查核人員投入較多資源，用以提昇審計強度、降低審計風險。本研究以公司自行申報收入數與審計核定年度收入間之差異，作為衡量審計強度的代理變數及迴歸的應變數，進行雙重差分模型(difference-in-difference model)分析，2016年及/或2017年關鍵查核事項含有收入的公司年度作為實驗組，其他公司年度為控制組，2010年至2015年為控制期間，2016年及2017年為實驗期間，若關鍵查核事項確實「關鍵」而有審計風險，則自行申報收入數與審計核定年度收入間應有顯著差異。研究結果顯示實驗組與控制組間之自行申報收入數與審計核定數無顯著差異。額外測試不區分實驗組與控制組於關鍵查核事項實施前、後的原有差異，若僅使用2016年及2017年度資料，二組間仍無顯著差異。若將樣本期間擴大為2010年至2017年，實驗組與控制組則有差異，仍源自期間因素而非關鍵查核事項。整體研究結果顯示關鍵查核事項內含的收入事項未能反映審計風險。

關鍵字

關鍵查核事項；查核風險；審計強度

並列摘要

Auditing Standards Bulletin No. 58 has required Audit Reports to reveal the most important issue discovered during the audit process since 2016. This Key Audit Matter regulation should attract more resources from auditors in order to decrease audit risks by increasing auditing strength. This study uses the difference between self-reported and audited annual revenue as a proxy for auditing strength and the dependent variable of regressions in a difference-in-difference model. The treatment group includes firm-years with 2016 and/or 2017 KAM of “revenues” and other firm-years are included as control group. Years 2010 to 2015 are used as control period, and years 2016 to 2017 as treatment period. If KAM is indeed a key audit matter that reveals audit risks, the self-reported revenue should significantly differ from the audited revenue. The result shows no significant difference in the two numbers between the treatment group and the control group. The additional test that does not control for treatment and control periods, also shows no difference between the two groups when sample period ranges from 2016 to 2017. There is significant difference between the treatment group and the control group when sample period ranges from 2010 to 2017. The difference causes from the term effect, not from KAM. The overall results reveal the inclusion of revenue as a KAM item does not reflex audit risks.