The World Economic Forum annual corruption index report published on Tuesday as part of its “Global Competitiveness Report”, ranked Nigeria 15th with Republic of Guinea behind Uganda, Nicaragua and Cameroon.

The WEF report, using a methodology linked to Transparency International’s Corruption Perception Index, covered 140 countries’ level of corruption within their societies on a scale of one to 100.

Based on the index, a score of 100 means a country is without corruption, while zero is the most corrupt possible. All the countries featured on this list scored 30 or less.

The countries regarded as most corrupt based on the WEF’s assessment criteria were in Africa, Central America, and the Middle East where the societies had weak legal and governmental systems and widespread poverty.

For instance, the WEF ranked Yemen, which is in the middle of a brutal civil war, as the most corrupt nation. But a handful of the world’s 20 largest economies also made it onto the list.

The 2018 edition of the Global Competitiveness Report represents a milestone in the four-decade history of the series, with the introduction of the new Global Competitiveness Index 4.0.

The new index throws light on an emerging set of drivers of productivity and long-term growth in the era of the Fourth Industrial Revolution.

In addition, it provides also the much-needed guide for policy-makers and other stakeholders to help shape economic strategies and monitor progress of their socio-economic reforms.