The Risk of Escalation in Serious Crime for Kidnap Offenders: A Modelling Approach

Kidnapping is a rare offence and is also rarely considered by researchers. We
extracted from the England and Wales Offenders Index all 7587 offenders (93%
males and 7% females) convicted of kidnapping from 1979 to 2001. We
examined the time from the first conviction for kidnapping to some specific
subsequent serious crimes: a subsequent kidnap, murder, manslaughter, and
rape of a female. Two survival analysis procedures - the Kaplan-Meier estimates
as a nonparametric procedure, and the Cox proportional hazards model as a
semi-parametric model - were used. Thus, one can estimate that 5 out of every
100 kidnap offenders convicted of kidnapping will be reconvicted for this offence.
In contrast, one in every 100 kidnap offenders will be convicted of homicide after
20 years and close to 2 out of every 100 will be convicted of rape of a female in
20 years. The number of previous conviction is a significant risk factor for each
of these serious reconvictions. Kidnappers are over 30 times more likely than
males in the general population to be convicted of homicide and four times more
likely than sex offenders. There should be, therefore, more focus on kidnappers
as a potentially dangerous set of offenders.