The Global Peace Index was launched this morning, serving up for the first time a measurement of exactly how peaceful 121 of the world's nations are. The ranking is based on the idea that peacefulness as a concept can be measured somehow, and their methodology -- tabulated by a team of academics and the Economist Intelligence Unit -- uses the expected external metrics as well as a surprisingly robust measurement of internal peacefulness. This includes indicators such as number of deaths from organized internal conflict, level of violent crime, ratio of police and internal security personnel to total population, and ratio of people in jail to total population.

Why the concentration on internal peacefulness?

Two sub-component weighted indices were then calculated from our group of indicators, 1) a measure of how at peace internally a country is; 2) a measure of how at peace externally (its state of peace beyond its borders). Our overall composite score and index was then formulated by applying a weight of 60% to our measure of internal peace and 40% for external peace. The heavier weight applied to internal peace was agreed within the group, following robust debate. The decision was based on the innovative notion that a greater level of internal peace is likely to lead to, or at least correlate with, lower external conflict—in other words, if ‘charity begins at home’ - so might peace.