2011年，哪个国家最和平?

MARY LOUISE KELLY, host: The world became slightly less peaceful in the last year. That's according to the new Global Peace Index, which attempts to rank 153 countries. Number one this year, Iceland. It replaces New Zealand, which held the top spot last year. And there are some surprises on the list. For more on that we've turned to Mark Quarterman, of the Center for Strategic and International Studies, which partnered with another think tank, the Institute for Economics and Peace, to help launch the index.

Hi, Mark.

Mr. MARK QUARTERMAN (Center for Strategic and International Studies): Hi. Good to be here.

KELLY: Good to have you here. So tell me, how do you measure a country's peacefulness? In a nutshell, what are the factors?

Mr. QUARTERMAN: There're a range factors from internal peace indictors that then include political stability, democracy, freedom of expression - to external issues as well - relations with neighbors, whether a country is engaged in war. They also include firearms, the percentage of the population incarcerated, GDP, per capita, among a range of other issues. Because they've found that peace is not an easy issue to define. And that it's also not an easy state to achieve.

KELLY: All right. So taking all of those factors together, Iceland, as we mentioned, came out number one - volcanic ash notwithstanding, I guess. I was trying to figure out which country might rank last. I was guessing it might be Afghanistan. Turns out this year it's Somalia.

Mr. QUARTERMAN: Turns out it's Somalia. And Iraq for the first time has moved from the bottom slot to the second to the bottom slot. And it's not just because the station in Somalia has worsened, but because the situation in Iraq has improved enough to improve its score.

KELLY: I gather the biggest changes in the rankings this year came from countries in the Middle East. Also in the Middle East, it got swept up in the Arab Spring. The single biggest fall was Libya.

Mr. QUARTERMAN: That's right. And of the top five states that have fallen in the rankings, three are countries that were swept up in the Arab Spring -Libya, Bahrain, and Egypt.

KELLY: Single biggest surprise on here, for me, was the U.S. ranking. The United States came in at 83 out of a 153 countries - barely struggling to make it in above Bangladesh, well behind China. Why is it so far down?

Mr. QUARTERMAN: There were a few factors that had an impact on the United States. One is the fact that it's involved in three wars around the world. Secondly, that it has the - by far the largest per capita incarceration（监禁，下狱） population in the world, and that's a factor considered in the Global Peace Index.

Third, that it has a very high firearm per capita ratio, as well. And it is relatively more violent in terms of murder and violent crime than other similarly wealthy countries. 

But here's the interesting - one of the interesting things about it for me. The U.S. is knocked down in part because of its involvement in wars, but it is involved in those wars in part because of what it perceives to be its responsibility as a global power.

And China, while it is certainly less democratic than the U.S. and respects human rights much less, has not been involved in international war.

KELLY: One of the criticisms of the index is it does not include, for example, indicators of violence against women and children. Should that be included?

Mr. QUARTERMAN: It could well be included. They don't specifically look at questions of violence against women and children. But they do look at gender equality in societies and found a very powerful correlation between societies that support gender equality and degree of peacefulness.

KELLY: Mark, thanks very much.

Mr. QUARTERMAN: Thank you very much.

KELLY: That's Mark Quarterman. He heads the Conflict, Crisis and Cooperation program at the Center for Strategic and International Studies, which helped to launch this year's Global Peace Index.

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