In this new report, Prof Paul Dolan provides an accessible guide into the latest developments in happiness research as they apply to the valuation of health. This report considers the degree to which happiness data can overcome some of the well-known problems with existing preference-based ways of valuing health. It presents new valuation data that show how the dimensions of health that matter most in happiness regressions are not the same as those that matter most when people are asked about their preferences. In particular, mental health matters more in happiness reports. One implication of using happiness to value health, then, might be that greater priority would be given to mental health than to physical functioning and pain.