In a context of confusion and flashy journalism, rigour becomes a precious value.
For the first time,Transparency International has also examined the relationship between corruption levels and the degree of freedom enjoyed by media and civil society groups.
More than 60% of the 176 countries analysed have serious corruption problems. This year, the index highlights the connection between corruption and inequality.
One in three citizens think corruption is one of the biggest problems facing their country. Ukraine, Moldova, Bosnia and Herzegovina and Spain are the worst judged.
Denmark (91) came out on top of the list for the second year in a row, followed by Finland (90) and Sweden (89). North Korea (8) and Somalia (8) are the most corrupt countries.