Is Joint Audit Bad or Good? Efficiency Perspective Evidence from Three European Countries

There is a constant questioning about the interest of introducing the joint audit. Very recently, the European Commission has raised this topic in its Green Paper, arguing that it may be a way to increase audit quality after the financial crisis and to mitigate audit market concentration, by enlarging the audit offer. However, the joint audit also faces strong resistance, consisting mainly in arguing an unbearable additional cost. This work tries to participate to the current debate by providing evidence based on the new institutional economics criteria of efficiency (i.e. cost or quality) that is relevant to justify an institutional mechanisms change. We run our main analysis on the Danish context (2005-2009), which gave up the mandatory joint audit in 2005. This change in regulation therefore provides a unique natural field to study the impact of joint audit within the same institutional setting. We test the impact of joint audit on both audit costs proxied by audit fees or total fees and audit quality proxied by abnormal accruals. Our results confirm the non significance of the association between total fees and joint audit, and between abnormal accrual and joint audit. We evidence a positive and significant relationship between audit fees and joint audit. Then we run an additional study on a matched French-German sample to capture the impact of a mandatory joint audit. France is characterized by a long tradition of joint audit while Germany has always experienced a single audit system. This additional analysis confirms the main result analysis. The results are of interest for regulators and actors in the audit market