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

The model is:
Number of
previous sex
offences Log (sentence length) = Median (sentence length) =
0 5.867 + 0.0005838.Age Exp (5.867 + 0.0005838.Age)
1 6.328 – 0.0027622.Age Exp (6.328 – 0.0027622.Age)
2 – 4 6.739 – 0.0079822.Age Exp (6.739 – 0.0079822.Age)
5 + 7.626 – 0.0226562.Age Exp (7.626 – 0.0226562.Age)
Figure 5 displays the fitted median sentence lengths for offenders over the age range
for each of the four categories of ‘number of previous sex offences’. The cross-over of
the curves is due to the scarcity of older males with large numbers of previous sexual
offences, rather than being an indication of paradoxical sentence lengths.
To interpret the curves, it is necessary to establish how an IAF 16+ of particular
severity might merit a particular sentence length. Having previous sex convictions
is likely to increase the sentence length. However, a young person with many
previous sex convictions will be seen as more ‘dangerous’ (therefore meriting a
stiffer sentence) than an older person with the same number of previous sex
convictions (whose sex offending has not had the same ‘intensity’).
Figure 5: Median custodial sentence lengths for indecent assaults of adult females
Median sentence length
1400
1200
1000
800
600
400
20
30
2-4
1
0
5+
40 50 60
Age of offender at murder conviction
49
70
APPENDIX A
80