The Tax Administration Series examines the fundamental elements of modern tax administration systems by using an extensive data set, analysis and country examples to highlight key trends, recent innovations and good practices.
First launched in 2004, the primary purpose of the series is to share information that will facilitate dialogue on the design and administration of tax systems.
Tax Administration 2025 is the thirteenth edition of the series. It provides comparative data on aspects of tax systems and their administration in 58 advanced and emerging economies. It includes performance-related data, ratios and trends up to the end of the 2023 fiscal year.
Listen to Episode 11.4 in Arabic, English, French, Mandarin, Portuguese, Russian, and Spanish on the following digital platforms: Soundcloud, Podbean, Apple podcasts or Spotify
Tax Administration 2025 presents the results of the last five rounds of the International Survey on Revenue Administration (ISORA) covering fiscal years 2018 to 2023.
The ISORA survey is a multi-organisation survey to collect information and data on tax administration. It is governed by five partner organisations: the Asian Development Bank (ADB), the Inter-American Center of Tax Administrations (CIAT), the International Monetary Fund (IMF), the Intra-European Organisation of Tax Administrations (IOTA) and the OECD.
While the ISORA surveys were completed by more than 170 administrations through the IMF’s Revenue Administration Fiscal Information Tool (RA-FIT), the 58 administrations included in Tax Administration 2025 correspond to the group of administrations supported by the OECD.
To provide further insight into the ISORA data in certain places, Tax Administration 2025 also uses data from the Inventory of Tax Technology Initiatives. The inventory is an online database containing information on technology tools and digitalisation solutions implemented by tax administrations across the globe. It has been developed by the OECD’s Forum on Tax Administration together with nine partner organisations.
Annex A contains an overview of the ISORA data tables that hold the latest available annual and periodic ISORA data for fiscal years 2018 to 2023, and that are published on the ISORA data portal (https://isoradata.org).
The ISORA data tables hold the data for the more than 175 jurisdictions that have completed at least one of the last five rounds of ISORA which were launched between September 2020 and September 2024. In addition to the ISORA data, the portal contains further information on ISORA, such as the survey questionnaires.