Five of the world's 20 safest cities, according to the The Economist's Intelligence Unit's Safe Index 2015, are American cities. New York City, ranked the 10th safest city in the world, is the sole American city in the top 10. San Francisco, Chicago, Los Angeles and Washington D.C. are also included in the list, ranked 12th, 16th, 17th and 19th, respectively.
In calculating the safest city rankings, The Economist considered factors other than crime statistics. Digital security, measuring the quality of a city's cybersecurity, the frequency of identity theft and other factors related to digital security all played a part in the calculations. New York City and Los Angeles were among the top cities in terms of digital security.
Health security, infrastructure and personal safety were the remaining three factors. Health safety took into account the average life expectancy of a city's citizens and the ratio of hospital beds to the size of the population. Infrastructure ratings measured the quality of roads and the number of people who die from natural disasters. Personal safety measured levels of crime, police engagement and violent crime.
The top five safest cities, according to The Economist's ratings, are Tokyo, Singapore, Osaka, Stockholm and Amsterdam. The remaining cities on the top 10 list are Sydney, Zurich, Toronto and Melbourne.