The GPI ranks 163 independent states and territories (collectively accounting for 99.7 per cent of the world's population) according to their levels of peacefulness.

The GPI is developed in consultation with an international panel of peace, experts from peace institutes and think tanks with data provided and processed by the Economist Intelligence Unit, a research and consulting company that provides analysis on the management of states and companies. The Index was first launched in May 2007, with subsequent reports being released annually. In 2007, it ranked 121 countries, up to 165 in 2015 and 163 this year.

The study was conceived by Australian technology entrepreneur Steve Killelea, and has been endorsed by individuals such as former UN Secretary-General Kofi Annan, the Dalai Lama, archbishop Desmond Tutu, the former United States president Jimmy Carter and other first plan international persons. The updated index is released each year at events in London, Washington, DC, and at the United Nations Secretariat in New York.

This year the ranking shows that 87 states have improved and 73 have deteriorated their attitude toward peace, but the world peace level as a whole has deteriorated by 0.07% and this is the ninth time in the past 13 years.

The best country remains, since 2008, Iceland followed by New Zealand, Denmark, Portugal and Slovenia. UK is (33^rd), after Qatar (29^th), Malaysia (23^rd) and Bhutan (22^nd). However, Europe remains the most peaceful continent. Two countries, the United States and Russia, ready to criticize the others, are respectively in 122^nd and 154^th place, with Turkey in between (149^th), all punished by their expansionist and aggressive foreign policy.

Africa remains the most geo politically unstable continent. The best countries are, in order, Mauritius (28^th), Ghana (38^th), Botswana (41^st), Sierra Leone (46^th), Gambia (53^rd), Senegal (54^th) and Tanzania (58^th). The worst were Libya (156^th), the Democratic Republic of Congo (157^th) and Somalia (158^th).

No African state is considered fully peaceful, even if the list is closed by three Middle Eastern countries - Syria (161^st), Yemen (162^nd) and, last for the fourth consecutive time, Afghanistan (163^rd) - which confirms this area as the least “peaceful” of ​​the world.

The Global Peace Index 2021 can be downloaded free. It is established thanks to the use of 23 indicators, some internal, such as the levels of violence and crimes and others aimed externally, such as military spending and military alliances.

The 2017 Global Peace Index suggested interesting annotations.

• Peace-building activities can be highly cost-effective, providing cost savings 16 times the cost of the intervention.
• The global economic impact of violence was $14.3 trillion PPP (Public Private Partnership) in 2016, equivalent to 12.6 per cent of global GDP, or $1,953 per person.
• In Low-Peace environments, the most important factors are related to Well-Functioning Government, Low Levels of Corruption, Acceptance of the Rights of Others and Good Relations with Neighbors.
• Due to armed conflict in the MENA (English-language acronym referring to the Middle East and North Africa), many related indicators such as deaths from internal conflict, number of refugees and IDPs, and organized internal conflict are at high levels.
• Safety and Security improved due to many countries recording a lower homicide rate and lower levels of political terror.

See also Ecco i Paesi più pacifici del mondo, la classifica del 2021 and Classement des pays par l'indice de paix globale (Global Peace Index) dans le monde and L'état de la paix dans le monde en 2021