Diagnostic surveys can provide vitalinformation for decisionmakers when institutional weaknessesinhibit a more regular flow of information. If strategicallydesigned, a survey can help induce policy change by pointingdirectly to the main bottlenecks, making it easier forpolicymakers to find solutions. This note summarizes twocases in Uganda where diagnostic surveys proved particularlyuseful. The first case involves public spending on healthand education; the second considers tax administration fromthe perspective of taxpaying firms.