Corruption Perception Index

Transparency International (TI) has published the Corruption Perceptions Index (CPI) since 1996, annually ranking countries "by their perceived levels of corruption, as determined by expert assessments and opinion surveys." The CPI generally defines corruption as "the misuse of public power for private benefit."

The CPI currently ranks 168 countries "on a scale from 100 (very clean) to 0 (highly corrupt)."

Transparency International commissioned of the University of Passau to produce the Corruption Perceptions Index (CPI). The 2012 CPI draws on 13 different surveys and assessments from 12 different institutions. The institutions are the African Development Bank, the Bertelsmann Foundation, the Economist Intelligence Unit, Freedom House, Global Insight, International Institute for Management Development, Political and Economic Risk Consultacy, Political Risk Services, the World Economic Forum, the World Bank and the World Justice Project.

Countries must be assessed by at least three sources to appear in the CPI. The 13 surveys/assessments are either business people opinion surveys or performance assessments from a group of analysts. Early CPIs used public opinion surveys.

The CPI measures perception of corruption due to the difficulty of measuring absolute levels of corruption.

A study published in 2002 found a "very strong significant correlation" between the Corruption Perceptions Index and two other proxies for corruption: Black Market activity and overabundance of regulation. All three metrics also had a highly significant correlation with real gross domestic product per capita (RGDP/Cap); the Corruption Perceptions Index correlation with RGDP/Cap was the strongest, explaining over three fourths of the variance. (Note that a lower index on this scale reflects greater corruption, so that countries with higher RGDPs generally had less corruption.

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