People also tend to be attracted to densely populated areas for the wider availability of job opportunities, goods and services. These mutually reinforcing forces yield important economic advantages for both consumers and firms: economies of scale, a better matching and functioning of labour markets, spillover effects and more technological intensity. It is no surprise that productivity, and therefore wages, tend to be higher in densely populated areas. The net impact varies from one urban area to another (OECD, 2015d).