Do large cities suffer from even greater incidence of crime? According to Bettencourt, et al. (2007), the number of crime follows super-linear relationship as a function of city size. For example, if the population size increases by 100%, the incidence of crime may increase by 120%. We analyzed...

Sustainable Development Goals adopted by The United Nations seek to protect and prevent the extinction of threatened species by 2020. Several countries even in the 1990s began expanding species protection to reach the 2020 goal early. This research investigates whether countries with low level...

By far, the most popular type of corruption measurements used is Corruption Perception Index published annually since 1995 by Transparency International. We examine whether country differences of the Corruption Perception Index existing in 2003 has narrowed by 2015 and if so, how fast. We deploy...