Researchers have used it when studying how to create closeness between individuals of different ethnic backgrounds and between groups that often distrust each other (for example, police officers and residents of low-income neighborhoods).

WSJ: Advice for Making New Friends: Share But Don't Overshare

Distrust of the GDP numbers has prompted Capital Economics, a research firm based in London, to create its own proxy of economic activity, which includes electricity output, domestic freight volumes, cargo traffic at ports, passenger transport and floor area under construction.

ECONOMIST: Is China overstating its true rate of growth?