Integration of financial and management accounting systems: The mediating influence of a consistent financial language on controllership effectiveness

► We conduct a study with controllers and managers in 149 of German Top-1500 firms. ► We examine the influence of an integrated MAS design on controllership impact on management decisions. ► We find that the influence is fully mediated by consistency of financial language. Two fundamental options exist for management accounting system (MAS) design: Either financial records can be used as a database for management accounting (integrated accounting system design), or the MAS can be based upon a separate system, i.e., a third set of books beside financial and tax accounting records. Since the 1990s, many German-speaking firms have changed from the second to the first option, which has instigated a highly controversial debate. Our paper contributes to this debate by empirically analyzing (1) whether the integration of financial and management accounting has a positive impact on controllership effectiveness, and (2) what causal inferences relate both variables. We use structural equation modelling for a sample of 149 dyads surveyed from German top 1500 firms. We identify no significant effect of the technical aspects of MAS integration, but a fully mediating influence of a consistent financial language on controllership effectiveness. Our results thus imply that consistency with financial reporting is an important property of MAS design from management's point of view.