A new sweeping meta-analysis has found no reliable link between economic inequality and well-being or mental health, challenging a long-held assumption that has shaped public health policy discussions for decades. The study, led by Nicolas Sommet at the University of Lausanne and Annahita Ehsan at the University of British Columbia, synthesized 168 studies involving more than 11 million participants across most world regions. The researchers screened thousands of scientific papers and contacted hundreds of researchers to compile the dataset, extracting more than 100 study features from each paper and linking them to more than 500 World Bank indicators. They also replicated their findings using Gallup World Poll data spanning 2005 to 2021, which surveyed more than two million respondents from more than 150 countries. People living in more economically unequal places did not, on average, report lower life satisfaction or happiness than those in more equal places. The average effect across studies was not statistically significant and was practically equivalent to zero. Studies that did find links between inequality and poorer mental health turned out to reflect publication bias, where small, noisy studies reporting larger effects were over-represented in the literature. The study adds: Further analyses showed that the near-zero averages conceal more-complex patterns. Greater income inequality was associated with lower well-being in high-inflation contexts and, surprisingly, higher well-being in low-inflation contexts. Greater inequality was also associated with poorer mental health in studies in which the average income was lower. We conclude that inequality is a catalyst that amplifies other determinants of well-being and mental health (such as inflation and poverty) but on its own is not a root cause of negative effects on well-being and mental health. Read more of this story at Slashdot.