There are two ways in which sociologists measure crime :
1). They analyse secondary data on crime gathered by the Government, which could include the official crime statistics (OCS), which are published quarterly and include crimes recorded by the police, and data from the government-sponsored victim (or victimization) survey - the Britsh Crime Survey (BCS).
2). They collect Primary Data by conducting victim surveys such as the Islington Crime Survey (ICS) carried out by the LEFT REALISTS, John Lea and Jock Young, or they might conduct self-report studies.