Evaluation of international corruption indexes: Should we believe them or not?

In this paper, we employ, and test the reliability and validity, of multiple corruption related datasets such as the Corruption Perceptions Index of Transparency International, the Control of Corruption Index of the World Bank, the International Country Risk Guide of PRS, the World Value Survey, the Bribe Payers Index, and the International Crime Victimization Survey. We find evidence that the reliability of international corruption indexes has improved over the years. However, a number of shortcomings – such as the risk of selection bias, longitudinal sensitivity, and measurement errors that are inherent in composite indexes – are commonly observed. These problems are critical enough to affect the results of empirical analysis, as we illustrate using linear models. Therefore, we conclude that researchers should pay more attention towards minimizing the impact of measurement error through rigorous data screening and robustness tests using multiple data sources and methods. A thorough and systematic evaluation of the reliability and validity of international corruption indexes is essential to increase their usefulness.