Murder and Serious Sexual Assault - Lancaster EPrints - Lancaster ...

APPENDIX C
‘murder-neutral’ and neither increases nor decreases the relative risk of murder. As,
however, this last conviction was custodial, there is a also a relative risk
contribution of 1.627. Multiplying these three contributions together, we obtain
1.987 x 1.329 x 1.627
or
4.296
From this model, this offender is over four times as likely to murder as the typical
petty offender is.
A risk score for SSA
A separate analysis was undertaken for the SSA cases. Table 18 below shows the
final model produced, which consists of 15 variables significantly contributing to
the risk score. The variables are listed in the order in which they were included in
the model. This again is a stable solution.
Of the summary measures, eleven produced an increased risk (shown by a positive
estimate in column 2 and a relative risk contribution above one in column 4) and
four lowered the risk.
It is immediately clear that there are some important features in the risk score. First,
attempted rape was by far the most significant and important risk factor in the score.
However, other sexual offences such as non-custodial indecent assault of an adult
female, unlawful sexual intercourse with a girl under 13, and, to a lesser extent,
unlawful sexual intercourse with a girl under 16, also contributed to the score (even
after controlling for the effect of attempted rape). Thus, those with a variety of
sexual offences against females were at a heightened risk of committing a SSA. In
contrast to the murder analysis, most of the unusual offences identified in Table 8
were present in this risk score (both kidnapping and cruelty to children were in the
final risk score). However, many of the risk factors which decreased the risk of SSA
were not present (receiving, fraud and other theft offences did not contribute to the
score). The number of previous sentencing occasions did enter into the score; the
risk decreased by a factor of 0.966 for every additional previous sentencing occasion
above the first one (which all offenders in this analysis had, by definition).
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