Security Rating is based on the Crime rating as well as the Terrorism rating of the city and it implies how safe the city is for residence. Other than analyzing factors such as number of crimes in the location, population of the location and other demographics attributes, we also analyze the occurrence of any recent terrorist incidents in the city. The parameter is then rated as Low, Medium, and High. Security rating as High means that the city is safe to live in. There is less crime rate as well as there has been no incident of terrorist attack.
Sources: Vision of Humanity (http://visionofhumanity.org/) which provides Terrorism Index. We also look at city specific websites, news articles, etc.