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World Tax Index


The World Tax Index (WTI) is an overall multi-criteria indicator of the tax burden. It combines hard tax data available from world-respected sources and national tax laws with soft data expressing Qualified Expert Opinion (QEO). The QEO has been gained from annual large-scale questionnaire survey conducted among tax specialist from all OECD countries. Experts from universities (University of OxfordMelbourne, or Princeton University), as well as other important institutions (European Central Bank, Austrian Institute for Advanced Studies, Japan Center for Economic Research and dozens of others) have been engaged. Their participation on the project has consisted in determining the weights of individual tax components on basis of multicriteria evaluation methods.

The index denotes the total value of the tax burden in relation to other countries under coverage, while higher WTI values indicate a higher tax burden. In the case of the WTI, interpretation of a tax burden does not apply only to the amount of the tax revenue and its relation to GDP, as in e.g. the case of a tax quota. There is a tendency to also include other important, legal above all, aspects in the tax burden evaluation that are connected, e.g. the progressivity of taxation, the administrative demands of tax collection, the extent of tax exceptions, deductions, tax credits, etc. For more information, see the WTI Structure & Methodology section.

The WTI as a whole represents more than 95% of the OECD tax mix in the countries under coverage. The remaining part of the mix refers to other taxes so specific for each country that their comparison is almost impossible.

The WTI was constructed by researchers from the VSB - Technical University of Ostrava, Czech Republic - Igor Kotlan and Zuzana Machova. During the research, Lenka Janickova, Milan Kastan, Rudolf Macek, and other colleagues and students also participated on the part concerning the QEO and in communication with tax specialists in general. For more information about the authors, see the About the Authors section.

The website is primarily intended for researchers and professionals dealing with tax issues and searching for a suitable index approximating the tax burden in OECD countries that can be used for the purpose of macroeconomic analyses as well as for legal comparison of tax systems of developed countries. You can download the WTI dataset here.


Although the WTI dataset is freely available, please respect that it is protected by copyright and trademark.