Internet Center for corruption research
HomeCorruption Perceptions Index2005Background information collage money students passau shaking hands
Home
Contact information
Research Area
Corruption Perceptions Index
2008
2007
2006
2005
2004
2003
2002
2001
2000
older indices
childhood days
Lecture and Workshops

Frequently Asked Questions

  1. What is the Corruption Perceptions Index?
  2. For the purpose of the CPI, how is corruption defined?
  3. Why is the CPI based only on perceptions?
  4. Is the CPI a reliable measure of a country's perceived level of corruption?
  5. Is the CPI a reliable measure for decisions on aid allocation?
  6. How many countries are included in the CPI 2005?
  7. Which countries are new to the CPI 2005?
  8. Is it right to conclude that the country with the lowest score is the world's most corrupt country?
  9. Which matters more, a country's rank or its score?
  10. Can country scores in the CPI 2005 be compared to those in past CPIs?
  11. Why isn't there a greater change in my country's score, given the strength (or: lack of) anti-corruption reform, or given recent exposure of corruption scandals?
  12. Which countries' scores deteriorated most between 2004 and 2005?
  13. Which countries' scores improved most?
  14. The CPI is more than ten years old. Are there any long term trends in country scores?
  15. What are the sources of data for the CPI?
  16. Whose opinion is polled by these surveys?
  17. Why include expert surveys, but not public opinion surveys?
  18. How is the index itself computed?
  19. Which countries might be included in future CPIs?
  20. What is the difference between the CPI and TI's Global Corruption Barometer (GCB)?
  21. What is the difference between the CPI and TI's Bribe Payers Index (BPI)?
What is the Corruption Perceptions Index?

The TI Corruption Perceptions Index (CPI) ranks countries in terms of the degree to which corruption is perceived to exist among public officials and politicians. It is a composite index, drawing on corruption-related data in expert surveys carried out by a variety of reputable institutions. It reflects the views of business people and analysts from around the world, including experts who are locals in the countries evaluated.

For the purpose of the CPI, how is corruption defined?

The CPI focuses on corruption in the public sector and defines corruption as the abuse of public office for private gain. The surveys used in compiling the CPI ask questions that relate to the misuse of public power for private benefit, with a focus, for example, on bribe-taking by public officials in public procurement. The sources do not distinguish between administrative and political corruption or between petty and grand corruption.

Why is the CPI based only on perceptions?

It is difficult to assess the levels of corruption in different countries based on hard empirical data, e.g. by comparing the number of prosecutions or court cases. Such cross-country data does not reflect actual levels of corruption; rather it highlights the quality of prosecutors, courts and/or the media in exposing corruption. The only method of compiling comparative data is therefore to draw on the experience and perceptions of those who are most directly confronted with the realities of corruption in a country.

Is the CPI a reliable measure of a country's perceived level of corruption?

In terms of perceptions of corruption, the CPI is a solid measurement tool. The reliability differs, however, between countries. Countries with a low number of sources and large differences in the evaluations provided by the sources (indicated by a wider confidence range) convey less reliability as to their score and ranking.

Is the CPI a reliable measure for decisions on aid allocation?

Some governments have begun to wonder whether it is useful to provide aid to countries perceived to be corrupt - and have sought to use corruption scores to determine which countries receive aid, and which do not.

TI does not encourage the CPI to be used in this way. Countries that are perceived as very corrupt can not be written off - it is particularly they who need help to emerge from the corruption-poverty spiral. If a country is believed to be corrupt, this should serve as a signal to donors that investment is needed in systemic approaches to fight corruption. And if donors intend to support major development projects in countries perceived to be corrupt, they should pay particular attention to 'red flags' and make sure appropriate control processes are set up.

How many countries are included in the CPI?

The CPI 2005 ranks 159 countries. TI requires at least three sources to be available in order to rank a country in the CPI. In 2004, the CPI included only 146 countries. The increase in coverage relates to the fact that a new source has been included.

Which countries are new in the CPI 2005?

The following countries are included in the CPI 2005, but were not in the CPI 2004: Afghanistan, Burkina Faso, Burundi, Cambodia, Equatorial Guinea, Fiji, Guyana, Laos, Lesotho, Liberia, Rwanda, Somalia, and Swaziland.

Is it right to conclude that the country with the lowest score is the world's most corrupt country?

No. The country with the lowest score is the one where corruption is perceived to be the highest among those included in the list. Moreover, there are more than 200 sovereign nations in the world, and the latest CPI ranks 159 of them.

Which matters more, a country's rank or its score?

While ranking countries enables TI to build an index, a country's score is a much more important indication of the perceived level of corruption in a country.

Can country scores in the CPI 2005 be compared to those in past CPIs?

The index primarily provides a snapshot of the views of business people and country analysts, with less of a focus on year-to-year trends.

If comparisons with previous years are made, they should only be based on a country's score, not its rank. A country's rank can change simply because new countries enter the index or others drop out. A higher score is an indicator that respondents provided better ratings, while a lower score suggests that respondents revised their perception downwards.

However, year-to-year changes in a country's score result not only from a changing perception of a country's performance but also from a changing sample and methodology. Each year, some sources are not updated and must be dropped from the CPI, while new sources are added. With differing respondents and slightly differing methodologies, a change in a country's score may also relate to the fact that different viewpoints have been collected and different questions been asked.

Why isn't there a greater change in a particular country's score, given the strength or lack of anti-corruption reform, or recent exposure of corruption scandals?

It is difficult to improve a CPI score over a short time period. The CPI is based on data from the past three years (for more on this, see question 15 on the sources of data, below). This means that a change in perceptions of corruption would only emerge in the index over longer periods of time. In addition, in those cases where government and/or others have made substantial efforts to combat corruption, with demonstrable results, and where there is no improvement in a CPI score, there is the possibility that these efforts - however successful - have not been adequately communicated.

Which countries' scores deteriorated most between 2004 and 2005?

Making comparisons from one year to another is problematic. However, to the extent that changes can be traced back to individual sources, trends can be cautiously identified. Noteworthy examples of a downward trend from 2004 to 2005 are Barbados, Belarus, Costa Rica, Gabon, Nepal, Papua New Guinea, Russia, Seychelles, Sri Lanka, Suriname, Trinidad & Tobago and Uruguay. In these cases, actual changes in perceptions occurred during the last three years.

Which countries improved most compared with last year?

With the same caveats applied, on the basis of data from sources that have been consistently used for the index, improvements can be observed from 2004 to 2005 for Argentina, Austria, Bolivia, Estonia, France, Guatemala, Honduras, Hong Kong, Japan, Jordan, Kazakhstan, Lebanon, Moldova, Nigeria, Qatar, Slovakia, South Korea, Taiwan, Turkey, Ukraine and Yemen.

The CPI is more than ten years old. Are there any long term trends in country scores?

The CPI was not designed to provide comparisons over time, since year-to-year changes on a country's score are the result not only of changes in perceptions of a country's performance, but of changes in survey samples and methodology and alterations in the list of sources that constitute the index. Nevertheless, analysis of the CPI and its component data, conducted by Prof. Dr. Johann Graf Lambsdorff in 2005, provides initial findings related to country trends in almost 60 countries over the period 1995-2005. For further detail see J. Graf Lambsdorff, 'Determining Trends for Perceived Levels of Corruption', Passau University Discussion Paper, V-38-06, 2005.

What are the sources of data for the CPI?

The CPI 2005 draws on 16 different polls and surveys from 10 independent institutions. TI strives to ensure that the sources used are of the highest quality and that the survey work is performed with complete integrity. To qualify, the data must be well documented and sufficient to permit a judgment on its reliability.

Data for the CPI has been provided to TI free of charge, on a non-disclosure basis. The institutions who provided data for the CPI 2005 are: Columbia University, Economist Intelligence Unit, Freedom House, Information International, International Institute for Management Development, Merchant International Group, Political and Economic Risk Consultancy, United Nations Economic Commission for Africa, World Economic Forum and World Markets Research Centre.

For a full list and details on questions asked, number of respondents and coverage of the 16 polls and surveys included in the CPI 2005, please see the CPI methodology at http://www.transparency.org/surveys/index.html#cpi or http://www.ICGG.org
Whose opinion is polled by these surveys?

Surveys are carried out among business people and country analysts, including surveys of residents of countries.

It is important to note that residents' viewpoints correlate well with those of experts abroad. In the past, the experts surveyed in the CPI sources were often business people from industrialised countries; the viewpoint of less developed countries was underrepresented. This has changed over time, giving increasingly voice to respondents from emerging market economies. In sum, the CPI gathers perceptions that are broadly based, not biased by cultural preconditions, and not generated just by American and European experts.

Why include expert surveys, but not public opinion surveys?

The CPI used to include public opinion surveys. When these surveys dropped out of the index because they were more than three years old, TI decided to focus the CPI exclusively on expert opinion on corruption. The reason for this is that while the surveys themselves don't distinguish between types of corruption, it was felt that business experts are better qualified than the public at large to comment accurately on grand corruption. The general public is assumed to be more familiar with the burden (or absence) of petty corruption within a country.

TI is interested in public assessments of the levels of corruption - particularly as a way to benchmark progress in the fight against graft. To this end, TI has developed another tool, the Global Corruption Barometer, to evaluate public sentiment on and experience with corruption (see question 20 on the difference between the CPI and the Global Corruption Barometer, below).

How is the index itself computed?

A detailed and a short description of the underlying methodology is available at http://www.transparency.org/surveys/index.html#cpi or at http://www.ICGG.org.

TI has made considerable efforts to ensure that the methodologies used to analyse the data are of the highest quality. The CPI methodology is reviewed by a steering committee consisting of leading international experts in the fields of corruption, econometrics and statistics. Members of the Steering Committee make suggestions for improving the CPI, but the management of TI takes the final decisions on the methodology used. The statistical work on the CPI is orchestrated at the University of Passau under the leadership of Prof. Dr. Johann Graf Lambsdorff.
Which countries might be included in future CPIs?

Countries with two sets of data are: Antigua and Barbuda, Bahamas, Bermuda, Bhutan, Cayman Islands, Central African Republic, Dominica, East Timor, Grenada, Guinea, Guinea-Bissau, Macau, Mauritania, North Korea, Puerto Rico and Togo. For all of the above countries, at least one more set of data is necessary for inclusion in the CPI.

Countries with only one set of data are: Andorra, Anguilla, Aruba, Brunei, Cape Verde, Comoros, Djibouti, French Guiana, Guadeloupe, Liechtenstein, Maldives, Martinique, Netherlands Antilles, Samoa, Sao Tome and Principe, St. Kitts & Nevis, St. Lucia, St. Vincent & the Grenadines and Virgin Islands (US). For all of the above countries, at least two more sets of data are necessary for inclusion in the CPI.

What is the difference between the CPI and TI's Global Corruption Barometer?

The CPI assesses the perception of levels of corruption across countries, while the Global Corruption Barometer (see http://www.transparency.org/surveys/index.html#barometer is concerned with attitudes toward and experiences of corruption among the general public. Over time, the Global Corruption Barometer, which was first published in 2003, will provide an indicator of the impact of the fight against corruption within countries.

What is the difference between the CPI and TI's Bribe Payers Index (BPI)?

While the CPI indicates overall levels of corruption in countries, the BPI focuses on the propensity of firms in leading export countries to bribe abroad - creating the 'supply side' of corruption. The BPI underlines the point that corruption in international business transactions involves those who give as well as those who take, and the BPI is therefore a complement to the CPI. The most recent Bribe Payers Index was published in May 2002 and can be found under: http://www.transparency.org/surveys/index.html#bpi.