In Bhutan, they measure progress not just by GDP, but also Gross National Happiness. This quiet, gently absorbing documentary follows two “happiness agents” as they travel door-to-door, like census workers, collecting data for the government’s happiness survey. There are 148 questions in total. Do you own a tractor? Goats? What about chickens? When was the last time you cried? Do you trust your neighbours? The agent compiles the answers into a table and crunches the data into an individual happiness score of between 0 and 10.

The impossibility of putting a number on happiness is quickly revealed. “How happy are you?”, one man is asked. “I’m as happy as the number of grains in my rice storage,” he replies. The agent marks that as a 7 out of 10. Then there’s a rich farmer who boorishly boasts of having three wives. He scores his life as a perfect 10, and answers on behalf of wife number one; she’s a 10 for happiness too, he says. If he bothered to look at her, he might notice the tears in her eyes.

Just as you’re wondering what score the wife would give herself, we hear from her talking privately about her relationship with the other wives. They’re as close as sisters; she can’t imagine life without them. They have a good laugh at the husband, too. “His belly got big,” says one. “His ass shrank though,” quips another. Then there’s a trans woman, whose happiness level of 3 is the lowest of the film, though scenes of her close relationship with her terminally ill mother are deeply moving. How can the survey quantify their bond?

Really, this is a film that quietly, intimately observes the lives of ordinary people. Co-directors Arun Bhattarai and Dorottya Zurbó are not interested in analysing the Gross National Happiness index, whether it’s a gimmicky stunt or if the government meaningfully translates it into policy. Increasingly, their focus settles on one of the happiness agents, Amber Kumar Gurung, a gentle soul, unhappily single in his 40s. That subplot of this lonely happiness agent gives the film the melancholic, gently ironic mood of an arthouse drama. Spoiler: Amber’s happiness score is 5.

• Agent of Happiness is in UK and Irish cinemas from 12 July.