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8. The effect of "pseudo reconvictions"

8.1 As noted in section 3.4, pseudo reconvictions are defined to be convictions which occur after the relevant date of the index conviction but which relate to offence(s) committed prior to that date. For example, this can arise in cases where there may be several sets of proceedings in train against an individual for offences committed on a range of dates. Pseudo reconvictions will therefore exaggerate the rate of "real" reconvictions to some extent. They will also complicate comparisons between reconviction rates for different types of disposal as they will tend to have less impact on the reconviction rates for offenders who are discharged from a custodial sentence relative to those given non-custodial sentences. Pseudo reconvictions will also tend to be more significant when considering reconviction rates for groups of offenders with a relatively high frequency of offending, such as younger offenders or those engaged in particular kinds of crime. Unless otherwise specified, all of the reconviction rates quoted in this bulletin include pseudo reconvictions. This should therefore be borne in mind when making comparisons between the reconviction rates for different types of disposal and offender.

8.2 Since the Scottish Offenders Index does not generally contain information on offence dates, the precise extent of pseudo reconvictions remains unknown. However, it is possible to estimate their impact by making use of the fact that the police case reference numbers associated with most convictions recorded in the Strathclyde Police Force Area, and increasingly in other police force areas, contain the month and year that the offence was recorded. (More recently it has also been possible to obtain actual offence date). This information can be used to derive a proxy for the date of offence (on the assumption that in the majority of such cases it will be close to the date the actual offence was committed). This proxy (or where available, actual) offence date for a reconviction can then be compared with the relevant date of the index conviction to determine whether or not it is a pseudo reconviction.

8.3 For 40,648 (87 per cent) of the cohort of offenders with an index conviction in 2003-04, offence dates for their convictions can be derived in the way described above. The profile of this subset of offenders, by sex, age, index disposal, index crime and number of previous convictions, is very similar to that of the cohort as a whole. It features the same gender split; the same proportion who were discharged from a custodial sentence, received a community sentence or probation; who had 1 or 2 previous convictions; and who had violent crime, sexual crime, dishonesty and drugs offences as their index crime. Therefore the fact that this is based on a subset of the 2003-04 is not judged to bias significantly this approach to estimating the effect of pseudo reconvictions.

8.4 Just under a quarter (23 per cent) of this subset of the 2003-04 cohort of offenders were reconvicted within two years for offences committed prior to the relevant date of their index conviction, i.e. had at least one pseudo reconviction within this period. However, just over 80 per cent of these offenders also had "real" reconvictions, i.e. in respect of offences committed after the relevant date of their index conviction. The overall two-year reconviction rate for this subset of the cohort was 46 per cent (slightly higher than the 45 per cent for the cohort as a whole). However, excluding pseudo reconvictions gives a "real" reconviction rate of 37 per cent. The average estimated effect of pseudo reconvictions is therefore 9 percentage points. Chart 3 illustrates the effect of excluding pseudo reconvictions over a 2-year follow-up period.

Table 16: Persons released from a custodial sentence or given a non-custodial sentence in 2003-04
Percentage reconvicted within 2 years

1. Offenders for whom the month and year of the offence(s) they are convicted for can be proxied by information embedded within the associated police case reference number.

Chart 3: Reconviction rates of offenders discharged from custody or given non-custodial sentences in 2003-04 (subset of data)

8.5 As reconviction rates vary with type of crime, age and other factors, so might the effect of pseudo reconvictions. This is explored further in Table 16. In general, those groups of offenders who tend to have higher reconviction rates also have higher rates of pseudo reconvictions, though the effect of these is generally offset by higher rates of "real" reconvictions.

8.6 The estimated effect of pseudo reconvictions on the reconviction rates for those discharged from a custodial sentence in 2003-04 was 8 percentage points whereas for offenders whose index conviction involved a community service or probation disposal the effect was 10 and 11 percentage points respectively. This will partly reflect the fact that the follow up time for reconvictions for the former group is taken from their estimated date of release from custody rather than the date they were originally sentenced to custody. Offenders released from custody, particularly those who have served relatively long sentences, might be expected to have fewer subsequent pseudo reconvictions.

8.7 The estimated effect of pseudo reconvictions ranged from 5 percentage points for those whose index crime was a sexual crime to 12 percentage points for other crimes and offences.

8.8 A comparison of the estimated effect of pseudo reconvictions on the two-year reconviction rates for each of the 1995-96 to 2003-04 cohorts of offenders is given in Table 17. There is in general little variation between the different cohorts.

Table 17: Persons released from a custodial sentence or given a non-custodial sentence, 1995-96 to 2003-04
Estimated impact of pseudo reconvictions on percentage reconvicted within 2 years ⁽¹⁾
Percentage points

1. Based on the subsets of offenders for whom the month and year of the offence(s) they are convicted for can be proxied by information embedded within the police case reference number.

Endnote

The statistics on reconvictions which are presented in this bulletin represent only a selection of those which can be derived from the information held on the Scottish Offenders Index. Work is being developed on producing predicted reconviction rates and career paths of offenders. Comments and suggestions for further analysis are welcomed. These should be directed to the enquiry point given at the end of this bulletin.

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