The index is a simple average of scores in 12 categories which are all given equal weight, grouped into three themes of basic human needs, foundations of wellbeing, and opportunity. There are between three and six indicators in each category.
Scores in each category are on a scale of zero to 100, where 100 is the maximum score by any country in the past decade and zero is the lowest score by any country in that period.
The new index is the latest of a series of attempts over the past 30 years to develop alternative measures of wellbeing after experts recognised the limitations of gross domestic product - a measure that counts rebuilding Christchurch as economic growth, for example, but not the destruction of buildings in the recent earthquakes.
Executive director Michael Green, a London-based economist, said others had tried to add new elements on to GDP, but the social progress index aimed to measure social and environmental "outcomes" directly rather than indirectly through indicators such as dollars being spent.
Kiwis underestimate what they have, says UK-born migrant
English-born David Ingram reckons New Zealand is freer than most Kiwis realise.
"I've been here 30 years next week," he said. "I think it's wonderful. I think Kiwis underestimate the freedoms they have."
The Herald went to the Auckland suburb of Onehunga yesterday to test one of the Gallup World Poll questions that gave this country top ranking in the Social Progress Index: "Are you satisfied or dissatisfied with your freedom to choose what you do with your life?"
Mr Ingram, 51, who was having coffee at the Baker's Cafe with grocery worker Tony Searle, 49, said New Zealand was exposed to many of the same threats as other countries but had preserved personal freedoms better.
"The ability to do what we want when we want, I'd say 10 out of 10 really," he said. "I can slag the Government off, I can do what I want, we have a very generous welfare system that looks after you when you get into trouble."
Mr Searle, who was born here, said he would like to earn a bit more and was concerned about a growing gap between rich and poor.
"We are starting to see a bit of an underclass in New Zealand. I think the rich have too much power," he said.
Cafe owner Chai Chay, 40, who came from Cambodia 14 years ago, works in the cafe seven days a week and struggles to make enough to feed his wife and two children after paying rent. But he is glad to be here.
"Cambodia is a very corrupt country ... I can't do anything. I have a house here. I like everything in New Zealand — environment, government, no corruption. But I feel a little bit upset because too much overhead."
Nutrition and basic medical care
The nutrition and basic medical care category measures the extent to which people's basic life support needs are met, including adequate food intake, the maternal death rate in pregnancy and childbirth, the number of stillbirths for every 1,000 live births, the death rate of children below age 5, and deaths from infectious diseases such as tuberculosis, measles and Aids.
New Zealand scored 28th, but our absolute score of 97.57 was only fractionally below the maximum score this year of 98.78 (Iceland).
New Zealand's worst indicator in this category was maternal deaths, with 15 deaths in pregnancy or childbirth or within 42 days after a termination for every 100,000 live births, compared with rates of only 7 in Australia and 2 in Greece and Estonia. However, Dr Sue Belgrave, who chairs New Zealand's maternal mortality review committee, said New Zealand records were more thorough than other countries.
Access to information and communications
Surprisingly, in this category New Zealand outranks the United States, where the internet was invented. Only 81% of Americans used the internet in 2012 compared with 89.5% of New Zealanders, more than in all but five other countries.
New Zealand also ranks first-equal with 10 other countries in press freedom, as ranked by Reporters Without Borders. A further nine countries are ranked 12th-equal, and the US and Australia are in a third tier of countries ranked 21st-equal.
However, New Zealand ranks only 57th on the third indicator in this category, mobile phone subscribers — even though we have more mobile phone subscriptions than people, 110 mobiles for every 100 people. Many poorer countries have more than this, such as Cambodia (129) and Kazakhstan (186), although they are likely to have fewer landlines than more developed countries.
Personal safety
Despite being in the lowest category for homicides, New Zealand and Australia both rated relatively low for personal safety because high numbers said yes to the question: "Is violent crime likely to pose a significant problem for Government and/or business over the next two years?"
On a scale of 1 (strongly no) to 5 (strongly yes), New Zealanders and Australians both averaged 2, compared with 1 in the United States.
But New Zealand's worst place in this category was for traffic deaths, with 9.1 deaths for every 100,000 people in 2010, ranking us 26th. Australia ranked 13th with 6.1 deaths for every 100,000 people, and the top-ranked country, Iceland, had only 2.8 deaths for every 100,000.
New Zealand's road toll has come down substantially since 2010, from 375 deaths in that year to 254 last year, or about 5.6 deaths for every 100,000 people.
Health and wellness
This is New Zealand's worst-scoring category, rating in the bottom half of the 130 countries for deaths from outdoor air pollution (71st behind the best), suicide (76th) and obesity (111th).
Deaths from air pollution range from 0 in Trinidad and Tobago, to 67 for every 100,000 people in Ukraine in 2008. New Zealand's death rate of 14 for every 100,000 people, mainly because of car exhaust fumes, compares with 7 for every 100,000 people in Australia but is better than in many European countries such as Denmark and the Netherlands (both 16) and the US (18). Obesity tends to be worse in richer countries such as the US (125th out of 130, or sixth-fattest), with Bangladesh first least-fat.
New Zealand also scores behind Australia on life expectancy, and deaths from non-communicable diseases between age 30 and 70. Australians live 82 years on average (sixth-best), one year longer than the average Kiwi (14th-best).
Ecosystem and sustainability
Oddly, the index measures greenhouse gas emissions per dollar of GDP, rather than the absolute level of emissions. Switzerland has the lowest greenhouse gas emissions per dollar of GDP. New Zealand is ranked second-best-equal along with 93 of the 130 countries including the United States, which is the world's biggest greenhouse gas producer.
Water use is measured as a proportion of total renewable water supplies. New Zealand is ranked 61st, using between 10% and 20% of the available supply — a level labelled "low to medium risk". Australia, ranked 109th out of 130, uses 40% to 80% of its water and is rated "high risk".
The third indicator counts the share of land ecosystems and territorial seas that are legally protected. New Zealand ranks 45th, protecting 14.3% of its land ecosystems and 16.9% of its sea area. Switzerland ranks first, protecting 17% of its land ecosystems.
Personal rights
New Zealand is ranked best in the world on all five indicators in this category: political rights, freedom of speech, freedom of association and assembly, freedom of movement and private property rights.
Political rights are assessed by another Washington think-tank, Freedom House, and include the electoral process, political pluralism and participation and the functioning of government.
Freedom of speech, assembly and movement are assessed by the Cingranelli-Richards (CIRI) Human Rights Data Project, run by a group of US academics.
Private property rights are from the conservative Heritage Foundation, which says New Zealand "property rights are strongly protected and contracts are notably secure. Enforcement of intellectual property rights is solid."
Personal freedom and choice
New Zealand is again ranked best in the world on corruption, sourced from Transparency International, and on freedom of religion, assessed by the Pew Research Centre based on the absence of any official policies to ban particular religions, prohibit conversions, limit preaching or give preference to one or more religious groups.
Kiwis rank second-equal with the Swiss, after the deeply Buddhist Cambodians, in the number of people who said yes to the question: "Are you satisfied or dissatisfied with your freedom to choose what you do with your life?" Australians came fourth.
But NZ ranks only 27th on availability of contraception, with 89.1% of women who want to avoid pregnancy actually using contraceptives in 2010, compared with 92.9% in the US and 96.2% in the top-ranked country, China.
New Zealand is again ranked best in the world on corruption, sourced from Transparency International, and on freedom of religion, assessed by the Pew Research Centre based on the absence of any official policies to ban particular religions, prohibit conversions, limit preaching or give preference to one or more religious groups.
Tolerance and inclusion
New Zealanders think of themselves as pretty tolerant. The nation came out first-equal with Canada for religious tolerance and second after Canada for tolerance of immigrants.
But NZ is slightly less tolerant of homosexuals, rating 10th after the Netherlands, Canada, Spain and six other developed countries when asked: "Is the city or area where you live a good place or not a good place to live for gay and lesbian people?"
NZ is rated 11th on discrimination, powerlessness and violence towards minorities — an indicator topped by a relatively homogeneous country, Iceland.
The nation's worst score in this category was a poll of women asking: "Do you believe that women in this country are treated with respect and dignity, or not?" New Zealand women rated NZ 21st, just behind Australia (20th).
Shelters
New Zealand scored the maximum possible on two indicators in this category — access to electricity (100 per cent) and deaths from indoor air pollution (zero).
But it was dragged down to 21st place overall by a Gallup World Poll question: "In your city or area where you live, are you satisfied or dissatisfied with the availability of good, affordable housing?"
"This is where New Zealand does not do so well compared to the Nordics," said Social Progress Imperative chief Michael Green.
Australia, where house prices are also high compared with incomes, scored only three places above NZ in 18th place. The United States, with more affordable housing, was ninth.
Access to advanced education
New Zealand rates fourth in access to tertiary education based largely on a single score — third place in the average years of tertiary education completed for people over 25.
The country rates 10th for the average total years in education, from primary to tertiary level, of women now aged 25 to 34.
And NZ rates 12th-equal with nine other countries on the number of globally ranked universities, with three each.
The index has no NZ data on the fourth item in this category, educational inequality.
Access to basic knowledge
New Zealand ranks second behind Japan for access to basic knowledge. Adult literacy is rated at 99%, primary and lower secondary school enrolment as near-universal, and the ratio of girls to boys in secondary schools at the maximum capped level of 1:1. (The ratio aims to measure exclusion of girls in poor countries, but there are more girls than boys in NZ high schools.)
Water and sanitisation
New Zealand and 10 other countries scored the maximum of 100 points for this category, which includes access to piped water, access to sanitation facilities, and compares rural versus urban access to improved water supply.
