“…However, earlier studies that report this association are particularly subject to methodological concerns (e.g., Barkess & Simnett, ; Firth, ; Palmrose, ; Simunic, ; for critical contributions and alternative explanations, Solomon, ; Firth, ; for evidence from the German audit market, Bigus & Zimmermann, ; Fleischer & Goettsche, ; for an overview, Hay, Knechel, & Wong, ). After adopting a two‐stage approach to account for potential endogeneity due to the joint determination of audit and nonaudit fees, the evidence of potential knowledge spillovers is less distinct; for example, for no effect see Abdel‐Khalik (), Whisenant, Sankaraguruswamy, and Raghunandan (), and Hay, Knechel, and Li (), and specifically for Germany, see Köhler and Ratzinger‐Sakel (); for a positive effect, see Antle, Gordon, Narayanamoorthy, and Zhou (); and for a negative effect, see Krishnan and Yu (), and specifically for Germany, see Krauss et al ().…”