While conventional wisdom holds that more competition between firms leads to a better product, a recent study published by the American Accounting Association has found that, at least in the case of internal audit opinions, this is not necessarily the case, according to AccountingWeb. Looking at 11,361 firm years between 2005 to 2011, the study found that audit clients not only tend to be quite successful as shopping for a clean audit opinion, its easiest in audit markets where there are relatively high levels of competition--meaning that firms are competing not to deliver the best, most accurate audit opinion but, rather, to produce the one that clients most want to hear. 

"Audit clients appear to be successful at shopping for clean internal control opinions. More specifically, our results suggest that clients would have received adverse internal control opinions more frequently if they had made different auditor retention or dismissal decisions." 

This, according to the study, makes intuitive sense as the more audit firms that exist in a market the more opportunities exist to take on new auditors who might give a different, more favorable opinion than their last ones. The study also found that timing also matters, as "auditor dismissals that occur relatively late in the reporting period are more likely to be associated with successful opinion shopping."