by imposing a severe penalty, theory is that the offender will think twice in the future, for fear of punishment such as a prison sentence, suspended sentence or heavy fine - however, prison does not appear to deter as 45% of adult prisoners reoffend within one year of release - critics: assumes that an offender will stop to consider the consequence of their action, but, most crimes are done in the spur of the moment so they are unlikely to stop and consider actions and consequences - fear of being caught is more of a deterrent