A Tale of Many Cities: Universal Patterns in Human Urban Mobility

The advent of geographic online social networks such as Foursquare, where users voluntarily signal their current location, opens the door to powerful studies on human movement. In particular the fine granularity of the location data, with GPS accuracy down to 10 meters, and the worldwide scale of Foursquare adoption are unprecedented. In this paper we study urban mobility patterns of people in several metropolitan cities around the globe by analyzing a large set of Foursquare users. Surprisingly, while there are variations in human movement in different cities, our analysis shows that those are predominantly due to different distributions of places across different urban environments. Moreover, a universal law for human mobility is identified, which isolates as a key component the rank-distance, factoring in the number of places between origin and destination, rather than pure physical distance, as considered in some previous works. Building on our findings, we also show how a rank-based movement model accurately captures real human movements in different cities

Evaluating the Efficiency and Productivity of Insurance Companies with a Malmquist Index: A Case Study for Portugal

This paper estimates changes in total productivity, breaking this down into technically efficient change and technological change by means of data envelopment analysis applied to a representative sample of insurance companies operating in the Portuguese market. The aim of this procedure is to seek out those best practices that will lead to improved performance in the market. We rank the companies according to their change in total productivity for the period 1995–2001, concluding that some companies experienced productivity growth while others experienced a decrease in productivity. The implications arising from the study are considered in terms of managerial policy. The Geneva Papers (2005) 30, 244–267. doi:10.1057/palgrave.gpp.2510029