Criminology is the scientific study of the causes and prevention of criminal behavior, informed by normative, legal and philosophical perspectives on scientifically established facts. In 1924, Edwin Sutherland defined Criminology as “the body of knowledge regarding crime as a social phenomenon that includes within its scope the process of making laws, of breaking laws, and of reacting toward the breaking of laws.” Criminologists are drawn from a wide range of disciplines including economics, history, law, psychiatry, psychology, political science, and sociology. Criminology is the study of crimes, criminals, crime victims, theories explaining illegal deviant behavior, the social reaction to crime, the effectiveness of anti-crime policies and the broader political terrain of social control. Criminology involves research to discover what really happens in the streets, in police stations and courts, behind prison bars, in board rooms, and on battlefields. Its practitioners are likely to engage in the systematic evaluation of the effectiveness of criminal justice policies and proposals, as well as the discovery of the socio-cultural, economic and global roots of crime, rates of crime and meaning of crime, or the diverse ways of measuring criminal activity and its impact. Criminologists typically collect and analyze data sets that may be quantitative, for example statistical studies on the rise and fall of crime rates, and/or qualitative, for example ethnographic studies on street subcultures and drug use.
The criminal justice main systems are: State: State criminal justice systems handle crimes committed within their state boundaries. Federal: The federal criminal justice system handles crimes committed on federal property or in more than one state. Law Enforcement: Law enforcement officers take reports for crimes that happen in their areas. Prosecution: Prosecutors are lawyers who represent the state or federal government