Corruption Perception Measurement

Corruption perception measurement quantifies how corrupt the public sector of a country is perceived to be, since actual corruption is hidden and cannot be observed directly. The canonical instrument, Transparency International's Corruption Perceptions Index (CPI), combines multiple independent expert assessments and business surveys into a single composite score per country. Each source is standardised onto a common scale and the rescaled scores are averaged, producing an index that ranks countries and tracks perceived integrity over time. The method explicitly reports uncertainty, echoing the aggregation logic of the World Bank's Worldwide Governance Indicators.