Happiness is a fuzzy concept, shifting in meaning from feeling good now to being satisfied with life in general. Happiness surveys are often about life satisfaction. Gallup and the OECD* both conduct life satisfaction surveys, although their approaches are quite different: 

Gallup: Please imagine a ladder with steps numbered from zero at the bottom to 10 at the top. Suppose we say that the top of the ladder represents the best possible life for you, and the bottom of the ladder represents the worst possible life for you. On which step of the ladder would you say you personally feel you stand at this time, assuming that the higher the step the better you feel about your life, and the lower the step the worse you feel about it? Which step comes closest to the way you feel?

OECD: On a scale of 0 to 10, please rate your general satisfaction with life.

Despite differences in framing**, the Gallup and OECD surveys yield pretty much the same picture of life satisfaction across countries. Here are the most satisfied countries:

Another sense of happiness is about experiencing positive emotions. Gallup has a survey for that too – and it seems that experiencing positive emotions and being satisfied with life don't necessarily go together:  country rankings are completely different. Latin American countries come out on top:

Finally, there are some surveys that just ask about happiness, like the US General Social Survey, which takes a middle-ground approach - how one feels "these days", not yesterday, not about life in general.

 

Next: what can we learn from all these surveys?

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*Organisation for Economic Co-operation and Development, a club of mostly rich countries.

**Since either way of approaching life satisfactions gets pretty much the same response, I don't see much point in the overly complicated "ladder" question.