Historically, a variety of methodologies have been used to gauge the size, nature and drivers of the burden imposed on businesses and others in complying with their tax obligations. While having their own set of features and distinct working objectives, the more commonly used methodologies are subject to a range of conceptual and practical limitations. In this article, the authors set out the findings of a study conducted across 47 countries in 2018, utilizing an innovative diagnostic tool and method for gauging compliance burden that has been developed for use in comparative cross-country assessments of the VAT compliance burden and its main drivers.