Corruption Perceptions Index
Summary: The Corruption Perceptions Index (CPI) ranks countries by their perceived levels of public sector corruption.
Main Points: The CPI, published by Transparency International (TI), scores and ranks countries/territories based on how corrupt a country’s public sector is perceived to be. It is a composite index, a combination of surveys and assessments of corruption, collected by a variety of reputable institutions.
Previously, the CPI was based on perceptions of corruption in each country/territory, relative to the other countries scored and ranked on this index. This was because the Index captured the rank position of each country in each data source, so that country scores were highly dependent on the changes in scores of the countries around it in the index. From 2012, we will be using the raw scores from each of the data sources, which provide greater transparency as to how the CPI scores have been constructed and better enable capturing changes over time.
Previous editions of the CPI drew on more than one year’s worth of data from the business surveys, where more than one year of data fell within the data period of the CPI. From 2012, we will only be using the most recent year’s worth of data from each source for each country. This will better show changes from one year to the next.
The Corruption Perceptions Index 2012 has been calculated using an updated methodology. The following steps are followed to calculate the CPI:
1. Select data sources: The Corruption Perceptions Index (CPI) 2012 is an aggregate indicator that brings together data from a number of different sources. Each data source must fulfill the following criteria to qualify as a source for the Corruption Perceptions Index:
· 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 and expected to be repeated regularly
· Allow for sufficient variation of scores to distinguish between countries
The CPI 2012 is calculated using different data sources from independent institutions that capture perceptions of corruption within the past two years. These sources are described in detail in the accompanying source description document.
2. Standardise data sources to a scale of 0-100 where a 0 equals the highest level of perceived corruption and 100 equals the lowest level of perceived corruption. This is done by subtracting the mean of the data set and dividing by the standard deviation and results in z-scores, which are then adjusted to have a mean of approximately 45 and a standard deviation of approximately 20 so that the data set fits the CPI’s 0-100 scale.
3. Calculate the average: For a country or territory to be included in the CPI, a minimum of three sources must assess that country. A country’s CPI score is then calculated as the average of all standardised scores available for that country. Scores are rounded to whole numbers.
4. Report a measure of uncertainty: The CPI is accompanied by a standard error and confidence interval associated with the score, which capture the variation in scores of the data sources available for that country/territory.
The dataset covers global sample of countries.
Access to database: www.transparency.org
Source: Corruption Perceptions Index 2012: An updated methodology
Page Created By: Madina Junussova. The content presented on this page is drawn directly from the source(s) cited above, and consists of direct quotations or close paraphrases. This material does not necessarily reflect the official view of the publishing organization.