Happiness may be one of the world’s least controversial things. Who among us doesn't want to be happy? As Aristotle put it: “Happiness is the meaning and the purpose of life, the whole aim and end of human existence.”

When it comes to measuring happiness, though, things get a little stickier and consensus becomes rather harder to maintain.

So just how do we go about it and why do we need to?

What money can't buy

The United Nations Secretary General, Ban Ki-Moon, noted in 2012 that for too long the world had used Gross National Product (GNP) to measure well-being.

Created in 1937 as a reaction to the great depression, GNP is useful for some things – but, Ban said, hopelessly limited. It does not consider any sense of well-being or contentment within a society.

And so each year, starting in 2012, 20 March has been designated International Happiness Day to recognize the importance of making happiness a goal of public policy.

How do you measure a feeling?

With so much inequality in the world, how can we possibly compare the happiness of the world’s richest and poorest people in a meaningful way? Happiness comes in many different forms and for different reasons. At the same time, many things make people unhappy regardless of where they live: losing a home or a loved one, or going without basic necessities.

Happiness is an aspiration of every human being, and can be a measure of social progress, according to the authors of the 2013 World Happiness Report, one of the first of its kind. They noted that the key to measuring happiness is differentiating between happiness as emotion (“I feel happy”) and as an evaluation of human well-being (“I am happy with my life”).

Their research sought to focus on the latter. Factors such as per capita gross domestic product, healthy years of life expectancy, trust and perceived freedom to make life choices were all considered.

Image: World Happiness Report, 2016

Some outcomes were unsurprising: Denmark led and other Scandinavian countries were among the happiest places on earth.

But other results didn’t follow obvious economic lines. Costa Rica was the 14th happiest country, only one place behind the United States and way ahead of the United Kingdom, which was 23rd.

Three elements

The findings are mirrored in another recent piece of research by Eurostat, focusing on Europe.

Image: Eurostat

In the European study, well-being was seen to consist of three distinct elements: 1) life satisfaction, 2) the presence of positive feelings and absence of negative feelings, and 3) “eudaimonics”, the sense that one’s life has meaning.

The self-reporting problem

These studies reply on self-reported levels of contentment – i.e. subjects are simply asked how they feel. But some psychologists have questioned the accuracy of this method, given that our view of our lives can be transient and highly subjective.

Framing happiness in terms of timely events instead can alter the outcomes. For instance, a Time Magazine survey and a Princeton University study both dealt with the happiness effects of sex. Time asked respondents about it from a reflective stance, whereas Princeton integrated experience sampling – i.e. they asked about the event just after it had happened.

In the Princeton survey, sex ranked as participants' most positive activity. The Time respondents, on the other hand, rated it far lower. The conclusion? Princeton participants weren't necessarily having a better time; rather, since the experience was fresher in their minds, the positive emotional effects may have registered more strongly.

Good enough

Condensing happiness down to a mere number or ranking overlooks much of the complexity and mystery involved in the emotion.