關係人交易存在利益衝突假說及效率交易假說兩種截然不同的觀點。關係人交易究竟係屬利益輸送的管道，或是效率經營的模式，過去文獻尚未獲得一致的結論，本研究認為這兩種截然不同的觀點並非無法同時存在，因此本研究探討關係人交易如果考量產業專家會計師事務所之後，是否可以抑制負面利益衝突的問題，並且促成正面效率交易的發生，亦即關係人交易與經營績效之關連性，是否存在產業專家之調節效果。實證結果發現：關係人交易會對公司的經營績效產生負向影響，然而納入產業專家之後，關係人交易與產業專家之交乘作用，會對公司的經營績效產生正向調節效果。實證結果支持產業專家能讓關係人交易由「利益衝突」轉為「效率交易」，產業專家會計師事務所能夠扮演除弊興利之角色，本研究為關係人交易的對立理論觀點及混亂實證證據提出一種解釋。

Two alternative views exist for the related party transactions, a conflict of interest view and an efficient transaction view. This study argues that both views do not always yield mutually exclusive conclusions. In this study, we attempt to disentangle the two contrasting views and predict that the association between related party transactions and firm performance is conditional on the moderating effect of auditor industry specialization. Empirical results reveal a negative relationship between related party transactions and firm performance, and a positive moderating effect of auditor industry specialization. This indicates that auditor industry specialization transfers the view of related party transactions from the conflict of interest to the efficient transaction. Thus, auditor industry specialization plays a moderating role in related party transactions. This study offers an explanation to the debate about the competing theoretical perspectives and the mixed prior empirical evidences of related party transactions.