The Corruption Perceptions Index (CPI) aggregates data from a number of different sources that provide perceptions by business people and country experts of the level of corruption in the public sector.

Each data source that is used to construct the CPI must fulfil the following criteria to qualify as a valid source:

• Quantifies perceptions of corruption in the public sector

• Be based on a reliable and valid methodology, which scores and ranks multiple countries on the same scale

• Performed by a credible institution

• Allow for sufficient variation of scores to distinguish between countries

• Gives ratings to a substantial number of countries

• The rating is given by a country expert or business person

• The institution repeats their assessment at least every two years

Okay so definitely some institution bias there.

13 data sources were used to construct the Corruption Perceptions Index (CPI) 2025:

1. African Development Bank Country Policy and Institutional Assessment 2023 (AFDB)

2. Bertelsmann Stiftung Sustainable Governance Indicators 2024 (SGI)

3. Bertelsmann Stiftung Transformation Index 2026 (STI)

4. Economist Intelligence Unit Country Risk Service 2025 (EIU)

5. Freedom House Nations in Transit 2024 (FH)

6. S&P Global Insights Business Conditions and Risk Indicators 2024 (GI)

7. IMD World Competitiveness Yearbook 2025 (IMD)

8. Political and Economic Risk Consultancy 2025 (PERC)

9. The PRS Group International Country Risk Guide 2025 (PRS)

10. World Bank Country Policy and Institutional Assessment 2024 (WB)

11. World Economic Forum Executive Opinion Survey 2025 (WEF)

12. World Justice Project Rule of Law Index 2025 (WJP)

13. Varieties of Democracy Project 2025 (VDEM)

Looking over the short blurbs in their methodology reads like a list of “freedom index think tanks” that are the exact people that claim it’s not corruption it’s lobbying. Especially when they land on conclusions like Israel is basically as corrupt as South Korea because we just mark the west bank and Gaza as no data…