The page lists the sources used for each of the categories, as well as defining in more detail what the category means. The definitions are probably broader tha

The page lists the sources used for each of the categories, as well as defining in more detail what the category means. The definitions are probably broader than you expect. E.g. "safety" does not just mean the absence of crime, but "The degree of safety provided by a city in more than a dozen key areas, including environmental, social and infrastructural security. Indicators include statistics on injuries and fatalities, damage caused at an economic level, public opinion data, and data on the vulnerability of a location to particular hazards."