Known unknowns

There's no question that good quality evidence is needed for public health policy development and decision making. But some topics are better served than others. A study by a team from McMaster University in Ontario attempts to map usage, quantity and quality of review level evidence coverage in a range of public health topics. The researchers, who examined the contents of the Canadian health-evidence.ca site, found that social determinants of health and healthy communities were amongst those most lacking in review evidence.