The creators of the Global Peace Index (GPI), the Institute for Economics and Peace (aka Vision of Humanity), claim that their index represents the first attempt that has been made to rank the nations of the world by their peacefulness. The GPI is apparently the brainchild of Australian entrepreneur, Steve Killelea, but has been developed in conjunction with the Economist Intelligence Unit and with the guidance of an international team of academics and peace experts.
As noted in the 2009 GPI report, peace is notoriously difficult to define. The approach adopted was to define peace as ‘absence of violence’ and to use metrics that combine both internal and external factors to rank144 countries. The Index is composed of 24 indicators covering three broad categories: measures of ongoing domestic and international conflict, measures of safety and security in society and measures of militarization.
The third category seems to me to raise a problem because it may sometimes be possible for us to promote peace more effectively by sending potential aggressors a credible message that if they mess with us they will suffer hellish consequences, rather than by disarming to convince them that we do not pose a threat. Instead of basing the index on the assumption that unilateral disarmament would promote peace I think it would have been preferable to leave this question open for further research.
For the benefit of potential users (such as myself) who are primarily interested in the internal peacefulness of different societies it would be desirable for the creators of the GPI to publish sub-indexes which exclude the effects of militarization (and international conflicts).
In view of the way the GPI has been constructed it is not surprising that a country like New Zealand, which does not have any reason to feel threatened by any other country, should be given the highest ranking as a peaceful country. The United States could be expected to have a somewhat lower ranking because of its greater militarization. I was surprised, however, that the GPI ranking of the U.S. is as low as 83 out of 144.
The relatively low ranking of the U.S is not entirely attributable to militarization. The percentage of the population in jail in the U.S. is apparently higher than in any of the other countries included in the index and the rate of homicide is higher than in New Zealand (and many other countries including Australia and the Britain).
The chart below indicates that it is possible for a country to have a relatively low GPI ranking while remaining relatively peaceful. For example, despite its relatively low ranking, the GPI score of the U.S. is much closer to that of New Zealand than to that of Iraq.
One final thought might be worth noting. This measure of the peacefulness of nations does not take account of the extent that different governments pursue policies that induce some of their residents to send their capital to other jurisdictions to avoid confiscatory taxation. This omission may be important for users who are interested primarily in the internal peacefulness of different societies.