Sleep hours fall as income rises: Macro and micro evidence on sleep inequality around the world

People spend about a third of their lives sleeping. Our paper utilizes detailed time-use data to study sleep inequality by income. Our contribution lies in analyzing this relationship both within and across countries, using a global sample. At the micro level, we find that full-time male workers in the top income quartile sleep around half an hour less per day than those in the lowest quartile. This qualitative result is robust to various alternative tests and measurement of key variables. At the macro level, the average sleep hours decrease as the country's GDP per capita increases. Interestingly, both our micro and macro estimations, are coherent with an estimated income elasticity of sleep around -0.04. Using this elasticity we replicate the implicit relationships identified in previous single-country studies. Additional results suggest that other leisure activities may be positively correlated to income, such as internet use and social outings, substituting sleep.