Criminal Proceedings in Scotland 2020-21: FOI release

Information requested

With respect to crimes of rape and attempted rape:

1. In Table 10(c) of Criminal Proceedings in Scotland 2020-21, does the word "average" refer to the mean?

2. Presuming it does refer to the mean, are you able to confirm the median and mode figures for each year 2011-12 to 2020-21?

3. If you are able to confirm the median and mode figures for each year, are you also able to provide a median and mode figure for (a) the entire date range and (b) the past 5 years?

4. In these circumstances, does Justice Analytics have a view on which figure (mean, median or mode) is:
a. most appropriate to understand first instance sentencing decisions in cases of rape/attempted rape; and
b. best at understanding trends over time in respect of first instance sentencing decisions in cases of rape/attempted rape.

Response

1. In Table 10(c) of Criminal Proceedings in Scotland 2020-21, does the word "average" refer to the mean?

1. Yes. Average refers to the arithmetic mean.

2. Presuming it does refer to the mean, are you able to confirm the median and mode figures for each year 2011-12 to 2020-21?

2. The median and mode are not published in the Criminal Proceedings in Scotland 2020-21 statistical bulletin but we are able to provide these on request and do so here in the table below. These are calculated using the same data as used to
calculate the mean values presented in Table 10c of Criminal Proceedings in Scotland 2020-21.

3. If you are able to confirm the median and mode figures for each year, are you also able to provide a median and mode figure for (a) the entire date range and (b) the past 5 years?

3. Again, these are not available in the Criminal Proceedings in Scotland 2020-21 statistical bulletin but we provide them in the table below (last two columns). Note that these are calculated by first “pooling” the data from the most recently available ten years (2011-12 to 2020-21) and five years (2016-17 to 2020-21) into single samples and are not an average of an average.

4. In these circumstances, does Justice Analytics have a view on which figure (mean, median or mode) is:
a. most appropriate to understand first instance sentencing decisions in cases of rape/attempted rape; and
b. best at understanding trends over time in respect of first instance sentencing decisions in cases of rape/attempted rape.

4. A mean is standard practice for representing the central value of sentence lengths in government statistics. Common exceptions are where extreme values are frequent (where a median is usually preferred) or the data are nominal (where a
mode may be preferred). In this specific case (see table, below) the mean captures more of the year-to-year variance than the median or mode, which both show no change at all between some years. Additionally, modes in particular can be complex to interpret as there may be multiple modes, as there are here in 2014-15. As such the mean has been selected as the best central value for understanding trends over time. Note that, as per our previous correspondence, we are not able to separate appeals from first instance decisions in this data.

Table. Average (mean, median, mode) sentence lengths(1) in days for people convicted in Scottish courts where the main charge was Rape and attempted rape, 2011-12 to 2020-21

Average	2011-12	2012-13	2013-14	2014-15	2015-16	2016-17	2017-18	2018-19	2019-20	2020-21	Last ten years2	Last five years3
Mean	2,264	2,450	2,507	2,381	2,549	2,502	2,578	2,655	2,445	2,435	2,496	2,535
Median	2,374	2,557	2,192	2,313	2,192	2,192	2,557	2,557	2,192	2,192	2,327	2,479
Mode	2,557	2,557	1,826	1,826 & 2,5574	2,192	1,826	3,287	2,192	1,826	1,826	1,826	1,826

1. Excludes life and indeterminate sentences as well as extended sentence portions.
2. These are calculated by pooling all data from the years 2011-12 to 2020-21 into a single sample.
3. These are calculated by pooling all data from the years 2016-17 to 2020-21 into a single sample.
4. The data were bimodal for this year.

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