Epidemiology is a science that was originally developed to study infectious diseases. Its major tools are statistical analysis of substantial data sets. In the past decades, the methods of epidemiology have been applied to suicide and homicide. This methodology is based on the assumption that both homicide and suicide are causes of death which can be analyzed in statistical manners and can be treated as public health issues. It steps away from assuming individual causes and motives of these kinds of deaths and instead looks for common environmental and demographic factors. For example, there are major correlations with age, gender, economic status, geographical location (certain neighborhoods have higher homicide rates than others), illegal drug use, ethnic background, etc.