It is widely presumed that preventing or addressing widespread corruption requires effective public institutions, supplemented by non-state actors, in a system of interlocking and interlinked institutions and actors (anti-corruption checks and balances). However there has been little evidence of the interactions and interdependencies between anticorruption mechanisms to enable empirical testing of theories that such institutionalised networks function as such, or have any relationship with reduced corruption. We use assessments of the performance of accountability roles of a diversity of institutions, on 19 indicators, in 38 countries using the National Integrity System approach, to test for the relationships between horizontal and vertical accountability, and the importance of each – and accountability in general – for policy and institutional reforms aimed at curbing corruption. We show that horizontal and vertical accountability are each measurable constructs, whose weakness or strength does tend to correlate; and that while causation is beyond the scope of this analysis, this accountability role performance also correlates separately and jointly with independent measures of corruption control. These results affirm the potential for holistic, country-based qualitative assessments of networked integrity institutions, as pioneered by the NIS approach, to deliver stronger evidence of how reforms to prevent and suppress corruption can be better targeted.