Existing experimental and quasi-experimental results have demonstrated that both anticorruption initiatives that provide information and/or authority to the recipients of government programs - so-called "bottomup" interventions - and initiatives that rely on government agencies for enforcement - "top-down" interventions - can be effective in some settings. Yet, in other instances, both forms of intervention have been found to be ineffective in combating corruption. These contrasting results strongly suggest that the effectiveness of both "top-down" and "bottomup" anticorruption interventions is conditional on other factors. Unfortunately, the existing literature says little regarding the conditions conducive to the success of either forms of intervention. Assessing the conditional effects of anticorruption treatments poses substantial challenges for researchers - particularly for those employing experimental or quasi-experimental approaches. This chapter (1) discusses factors that may condition the effectiveness of both top-down and bottomup interventions; (2) illustrates the difficulties in assessing these conditional relationships, with particular reference to experimental and quasi-experimental settings; and (3) suggests approaches that might mitigate these problems.