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Methodology and Data Sources
The indicators Twenty-four indicators of the existence or absence of peace were chosen by the panel, which are divided into three key thematic categories. Many of the indicators have been "banded" on a scale of 1-5; qualitative indicators in the index have been scored by the Economist Intelligence Unit's extensive team of country analysts, and gaps in the quantitative data have been filled by estimates. Indicators of quantitative data such as military expenditure or jailed population have been normalised on the basis of: x = (x-Min(x)) / (Max (x) - Min (x)) Where Min (x) and Max (x) are respectively the lowest and highest values in the 140 countries for any given indicator. The normalised value is then transformed from a 0-1 value to a 1-5 score to make it comparable with the other indicators. Measures of ongoing domestic and international conflict The Global Peace Index is intended as a review of the state of peace in nations over the past year, although many indicators are based on available data from the last two years. The advisory panel decided against including data reflecting a country's longer-term historical experience of domestic and international conflict on the grounds that the GPI uses authoritative statistics on ongoing civil and trans-national wars collated by institutes such as the Uppsala Conflict Data Program and the International Peace Research Institute, Oslo. These, combined with two indicators scored by the Economist Intelligence Unit's analysts, comprise five of the 24 indicators.
Ten of the indicators assess the levels of safety and security in a society (country), ranging from the level of distrust in other citizens, to the level of respect for human rights and the rate of homicides and violent crimes. Crime data is from the UN Office of Drugs and Crime (UNODC). Five of these indicators have been scored by the Economist Intelligence Unit's team of country analysts.
Nine of the indicators are related to a country's military build-up - reflecting the assertion that the level of militarization and access to weapons is directly linked to how at peace a country feels internationally. Comparable data are readily available from sources such as the International Institute of Strategic Studies (IISS).
The advisory panel apportioned scores based on the relative importance of each of the indicators on a 1-5 scale. Two sub-component weighted indices were then calculated from the GPI group of indicators, 1) a measure of how at peace a country is internally; 2) a measure of how at peace a country is externally (its state of peace beyond its borders). The overall composite score and index was then formulated by applying a weight of 60% to the measure of internal peace and 40% for external peace. The heavier weight applied to internal peace was agreed within the advisory panel, 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. GPI Year-on-Year Comparison The expansion of the GPI from 121 countries to 140 does not lend itself to direct comparisons of changes in rank as the introduction of a number of countries instantly pushes various countries downwards. The normalisation of a number of our series for our index also makes direct year-on-year comparisons difficult as the normalised series essentially measure countries in direct reference to their respective differences for that given time period (maximums and minimums will differ between the 2007 GPI measurements and 2008). Nevertheless, we have developed a special comparative version of the Global Peace Index in 2008 for the original 121 countries. The comparison excludes new 2008 countries. |
