How Reliable Are Global Quantitative Corruption Statistics? A New U4 Report Suggests the Need for Caution

Those who work in the anticorruption field are likely familiar with the frequent citation of quantitative estimates of the amount and impact of global corruption. Indeed, it has become commonplace for speeches and reports about the corruption problem to open with such statistics—including, for example, the claim that approximately US$1 trillion in bribes are paid each year, the claim that corruption costs the global economy US$2.6 trillion (or 5% of global GDP) annually, and the claim that each year 10-25% of government procurement spending is lost to corruption. How reliable are these quantitative estimates? This is a topic we’ve discussed on the blog before: A few years back I did a couple of posts suggesting some skepticism about the US$1 trillion and US$2.6 trillion numbers (see here, here, here, and here), which were followed by some even sharper criticisms from senior GAB contributor Rick Messick and guest poster Maya Forstater.

This past year, thanks to the U4 Anti-Corruption Resource Centre, I had the opportunity to take a deeper dive into this issue in collaboration with Cecilie Wathne (formerly a U4 Senior Advisor, now a Project Leader at Norway’s Institute for Marine Research). The result of our work is a U4 Issue published last month, entitled “The Credibility of Corruption Statistics: A Critical Review of Ten Global Estimates.” (A direct link to the PDF version of the paper is here.)

In the paper, Cecilie and I identified and reviewed ten widely-cited quantitative estimates concerning corruption (including the three noted above), tried to trace these figures back to their original source, and assess their credibility and reliability. While the report provides a detailed discussion of what we found regarding the origins of each estimate, we also classified each of the ten into one of three categories: credible, problematic, and unfounded.

Alas, we could not rate any of these ten widely-cited statistics as credible (and only two came close). Six of the ten are problematic (sometimes seriously so), and the other four are, so far as we can tell, entirely unfounded. Interested readers can refer to the full report, but just to provide a bit more information about the statistics we investigated and what we found, let me reproduce here the summary table from the paper, and also try to summarize our principal suggestions for improving the use of quantitative evidence in discussions of global corruption: Continue reading