本研究以裁決性應計數作為衡量審計品質之代理變數，並採用赫芬達爾—赫希曼指數作為衡量客戶集中度之基礎，探討會計師客戶集中度與審計品質間之關聯性，並進一步探討會計師客戶集中高低程度對於會計師客戶組合中不同客戶規模之影響。實證結果顯示，在控制影響審計品質之相關變數後，個別會計師客戶集中度越高，裁決性應計數絕對值越大，而造成此一現象主要源自於個別會計師客戶組合中規模較小者具有較差的審計品質。本研究推論此實證結果係因會計師客戶集中程度會造成會計師扭曲分配其所擁有之查核資源，影響所提供之審計品質。

Contemporary studies have generally discussed whether the individual auditor maintains their independence for economically important clients. Different from these studies, we used the Herfindahl-Hirschman Index as a measure of auditor client concentration to examine whether the latter affects audit quality by using a sample of Taiwan listed companies over the period of 2006-2015. The empirical results indicate that high auditor client concentration leads poor audit quality. We further examined the negative relationship between auditor client concentration and audit quality in the auditor’s client pool and found evidence suggesting that auditors provide significantly worse audit quality for small companies.

李建然、陳信吉與湯麗芬（2013），客戶重要性與審計品質—從簽證會計師角度分析，當代會計，第14卷第2期：147-174。
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