The ratings that I am writing about are the ladder of life ratings from the Gallup World Poll – the top step of the ladder represents the best possible life and the bottom step represents the worst possible life. But I could be referring to any of a range of surveys that ask people to place a numerical rating on how happy they are or on how satisfied they are with their lives.
I do not intend to argue that New Zealanders have a peculiar propensity to over-rate their satisfaction with their lives. The issue I want to discuss is what it means when surveys show that New Zealanders are just as satisfied with their lives as people in the U.S. even though average incomes in NZ are only about two-thirds of the U.S. level. I propose to compare the impact of income differences and other factors on the survey measures of subjective well-being in order to enable readers to consider whether the impacts attributable to income differences provide an accurate measure of its impact on the quality of lives.
It is now possible to make fairly accurate comparisons of the impact of income and other factors on average ratings of subjective well-being at a national level. Recent research by John Helliwell, Christopher Barrington-Leigh, Anthony Harris and Haifang Huang has shown that a high proportion of differences in average life evaluations between countries can be explained statistically by differences in a relatively small number of variables reflecting social, institutional and economic circumstances of life (See Table 3, ‘International Evidence on the Social Context of Well-being’, Working paper 14720, NBER, 2009). The most important variables are income (log of per capita GDP), friends (the proportion of survey participants who have relatives or friends they can count on for help when they are in trouble), freedom (the proportion who satisfied with their freedom to choose what they do with their lives) and corruption ( responses to questions relating to whether corruption is widespread throughout government and business).
In the Figure below I have used these research results to show reasons why average survey measures of subjective well-being in several countries differ from the U.S. ratings.
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The net differences from U.S. ratings are shown next to the label for each country. If you focus on New Zealand you can see that the perception of NZers that their country is relatively free of corruption outweighs the negative impact on survey responses of the fact that average incomes in NZ are substantially lower than the U.S. average.
If you consider that corruption is as big a problem in the U.S as, for example, in Greece, you might think that this provides an accurate depiction of the relative impacts of income differences and corruption on the quality of life in New Zealand and the U.S. However, when I look at the expert ratings of corruption levels in Transparency International’s corruption index, the U.S. doesn’t look too bad. The rating of the U.S. in this index (7.3) is lower than Denmark and NZ (both on 9.3) and Australia (8.7) but well above Italy (4.8) and Greece (4.7). (It is also interesting that Greeks do not perceive that their corruption problem to be any worse than that in he U.S. and that NZers do not perceive themselves to be as free of corruption as the Danes).
The point is that the influence of various factors on the survey ratings of quality of life depends on the way they are perceived. The ratings are more like emotional responses than dispassionate evaluations. It seems to me that self-reports of how people feel about their lives tell us about their emotional states - which are an important component of well-being but do not tell the whole story.
One way to test survey ratings is to ask ourselves to what extent we would be prepared to rely on them in making decisions affecting our own well-being. It seems to me that income may be more important to people when they make decisions affecting their well-being than when they answer questionnaires about the quality of their lives. If you were in Europe contemplating a choice between moving your family to either the U.S. or NZ, would you consider the importance of differences in average income levels to be adequately reflected in survey ratings of the quality of life?
Postscript:
Survey ratings can also be tested by comparing them with actual migration patterns where free migration is allowed - as between New Zealand and Australia. Migration statistics for New Zealand show that in recent years permanent and long-term departures to Australia have exceeded arrivals from Australia by a factor of more than 3:1.