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What is the Corruption Perceptions Index?

The TI Corruption Perceptions Index (CPI) this year ranks 90 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 16 different polls and surveys from 8 independent institutions carried out among business people, the general public and country analysts.

For the purpose of the TI indices, how is corruption defined?

TI 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 tend to ask questions in line with the misuse of public power for private benefits, with a focus, for example, on the bribing of public officials or giving and taking of kickbacks in public procurement.

What role is played by exporters in international criminal transactions?

In 1999, TI published an additional index, which ranked exporting countries according to their propensity to offer bribes. This Bribe Payers Index (BPI) is available online (PDF-document). The BPI complements the CPI and underlines the point that corruption in international business transactions involves both those who take and those who give Looking only at those who take, as is suggested by the CPI, provides an incomplete picture and a new BPI is planned for next year.

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

No. Transparency International bends over backwards to convince journalists and others that this is a false interpretation. Firstly, there are over 200 sovereign nations in the world and the CPI only ranks 90 - TI does not have sufficient reliable data for all countries. Secondly, the CPI is based on polls, which are snapshots in time and solely reflect opinions.

Why is the CPI based on perceptions only?

It is impossible to base comparative statements on the levels of corruption in different countries 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 build on the experience and perceptions of those who are most directly confronted with the realities of corruption. The CPI is based on 16 polls and surveys. Some of these are surveys of residents, including locals and expatriates. Of these, some poll the public at large while others target business elites. Another group of polls is based on the analysis of country experts, largely non-resident.

What are the criteria in determining which surveys are used?

TI seeks excellent data for the CPI and to qualify, the data has to be well documented and reliable. TI strives to ensure that the sources used are of the highest quality, that the survey work is performed with complete integrity and that the methodologies used to analyse findings are first class. TI is confident that these criteria apply to the CPI. A more detailed description of the underlying methodology has been written for the 2000 index to be obtained at or The methodology used is reviewed by a TI 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 for establishing the CPI. Consequently, neither the CPI methodology nor its presentation modality ought to be interpreted as necessarily constituting endorsement by the Steering Committee or its individual members.

Which countries are included in the 2000 CPI?

TI requires at least three sources from independent institutions to be available for a country before TI considers the database sufficiently robust for that country to be ranked in the CPI. Countries for which there might only be one or two data sources available is are not included in the CPI.

Are old surveys used in the CPI?

The CPI is based on 1998-2000 data. Fundamental changes in the levels of corruption in a country only evolve slowly, while public perceptions may change more swiftly and be influenced to some extent by short-term events, TI determined to base the CPI on a three year rolling average. Thus, this year's CPI is based exclusively on survey data collected between 1998 and 2000.

Which sources have contributed to the assessment of each individual country?

Please see the final pages of this press release information package for the list of sources and surveys from which the CPI is derived. A list of the sources that contributed to the assessment of each country can be obtained via the Internet as an Excel-sheet. This list also provides further information on standard errors and confidence intervals for each country.

Can data from one year be compared with that from a previous year?

This is somewhat problematic. The CPI incorporates as many reliable and up-to-date sources as possible. One of the drawbacks to this approach is that year-to-year comparisons of a country's score do not only result from a changing perception of a country's performance but also from a changing sample and methodology. Some sources are not updated and must be dropped as a result, while new, reliable sources are added. With differing respondents and slightly differing methodologies, a change in a country's score cannot be attributed solely to actual changes in a country's performance. Comparisons with the views collected in previous years can therefore be misleading.

Is the country score 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 is different, however, for different countries. Countries with a low number of sources and large differences in the values by the sources (indicated by a large Standard Deviation) do convey less reliability as to their score and consequently their ranking. To strengthen understanding of the range of individual survey results for each country TI this year not only includes a column on Standard Deviation in its ranking table, but also a column that shows the High - Low Range of the survey scores.

Why did TI provide a high-low range this year?

For some countries our sources exhibit significant differences in their scores. While this has always been indicated through high Standard Deviations, TI was asked to note the highest and lowest score per country in order to even more explicitly display the width of the assessments.

Do large high-low differences automatically suggest that a country's score is measured imprecisely?

No, not necessarily! Countries with three or eleven sources can have the same high-low range, but in the latter case one can feel much more confident about the country's score if the Standard Deviation is not too high.

Which countries' scores deteriorated most between 1999 and 2000?

As repeatedly said, making comparisons from one year to another is problematic. However, to the extent that changes can be traced back to the change in individual sources, trends can be cautiously identified. Remarkable examples for a downward trend are Zimbabwe, Ukraine and the Philippines. The considerable decline in their scores does not result from technical reasons - actual changes in perceptions are therefore likely. Noteworthy is also the deteriorating performance of Germany and Ireland.

Which countries improved most as compared to 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 for Croatia, Belgium, Spain and Japan.