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

APPENDIX A
However, the estimated median sentence length is, for each category of number of
previous convictions, a continuous function of age. In fact, the majority of sentence
lengths fall exactly on a certain number of months or years: 1 year, 15 months, 18
months, 21 months, and then 2, 2 1/2, 3, 3 1/2, 4, 4 1/2, 5, 6, 7, 8, 9, 10 years. It
therefore seemed appropriate to create step functions for each of the previous
convictions categories to reflect this.
Using the predicted median sentence length for each age and number of previous
sex offences, the next ‘important’ sentence length has been taken as the cut-off
point; an offence receiving this sentence length or more can be classed as ‘serious’.
The values to be used to define a ‘serious’ indecent assault of a female aged 16 or
over are therefore:
Number of
previous sex
offences Conviction age ‘Serious’ offences have sentence lengths:
0 All 15 months (456 days) or more
1 All 18 months (547 days) or more
2 – 4 15 – 35 2 years (730 days) or more
36 – 55 21 months (638 days) or more
56 onwards 18 months (547 days) or more
5 + 15 – 20 4 years (1460 days) or more
21 – 30 3 1/2 years (1277 days) or more
31 – 40 3 years (1095 days) or more
41 – 50 2 1/2 years (912 days) or more
51 – 60 2 years (730 days) or more
61 onwards 18 months (547 days) or more
These are sentences of immediate imprisonment, whether in an adult or young persons
institution. In addition, those offences for which the disposal was a ‘Restriction
Order’ are also classed as ‘serious’.
In Figure 6, a separate plot is produced for each of the four categories for the number
of previous sex offences. In each plot, the appropriate fitted line for the median
sentence length (seen in Figure 5) is displayed, with the ‘step function’
superimposed. Sentence lengths that fall on the step function or above it are deemed to
have been awarded to a ‘serious’ indecent assault of a female aged 16 or over.
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