This Helpdesk Answer provides an overview of publicly accessible tools that assess a country’s level of corruption or its performance in controlling corruption and adhering to good governance benchmarks. The paper also includes tools that relate to the enabling environment and measure variables such as transparency, civic space or press freedom believed to reduce the risk of corruption. These assessment tools draw on a range of qualitative and quantitative data sources, including composite indexes, expert appraisals, experience- and perception-based survey instruments and in some cases administrative data. The paper is an updated version of the 2013 How-to guide for corruption assessment tools and 2016 How-to guide for corruption assessment tools.