Journey times in the Scottish Criminal Justice System: analysis of equality factors of accused disposed in court

An accused’s journey time is taken to be the time between the earliest offence date in a specific case and the latest verdict date in that case.

The calculations presented in this paper are based on the same information used in the Journey times in the Scottish Criminal Justice System bulletin. Some accused have been excluded from journey times calculations due to missing dates (approximately 5% of all accused prosecuted in Scottish criminal courts).

Analysis by the equality related factors of sex, age, ethnic group and Social Index of Multiple Deprivation (SIMD) 2020 is possible using the journey times data set.

In this data set, information on sex is generally based on a person’s physiology as perceived and recorded by a police officer. SCTS refer to sex rather than gender because this better reflects recording practices in relation to this information. The information is recorded on Police Scotland systems and will be electronically transferred to Crown Office and Procurator Fiscal Service (COPFS) systems and then from COPFS onto the Scottish Courts and Tribunals Service (SCTS). Sex information is missing in 0.7% of the records.

Age bands are based on the accused age at the time the case was registered by SCTS. Age is based on a person’s date of birth as recorded by a police officer. The information is recorded on Police Scotland systems and will be electronically transferred to Crown Office and Procurator Fiscal Service (COPFS) systems and then from COPFS onto the Scottish Courts and Tribunals Service (SCTS). Age information is missing in 0.2% of the records.

In this data set, ethnicity is generally based on a person’s physiology as perceived and recorded by a police officer. SCTS refer to ethnicity rather than race because this better reflects recording practices in relation to this information. The information is recorded on Police Scotland systems and will be electronically transferred to Crown Office and Procurator Fiscal Service systems (COPFS) systems and then from COPFS onto the Scottish Courts and Tribunals Service (SCTS). Ethnicity information is missing in 14.6% of the records.

Socio-economic background is measured using the Scottish Index of Multiple Deprivation (SIMD) 2020.  SIMD shows how each area ranks against others against the set of SIMD indicators. SIMD is calculated by SCTS and is based upon the last known postcode available for an accused on their management information system. If the postcode does not map directly to SIMD, then a SIMD value will not be available for that accused.  For example if the accused supplies a non-Scottish postcode, the postcode inaccurate or no postcode is available there will be no SIMD value. SIMD information is missing in 23.4% of records.

Further information on the SIMD is described here:

SIMD rank to quintile, decile, and vigintile - gov.scot (www.gov.scot)

The SIMD is a relative measure of deprivation across 6,976 small areas (data zones). If an area is identified as ‘deprived’, this can relate to people having a low income but it can also mean fewer resources or opportunities. SIMD ranks data zones from most deprived (ranked 1) to least deprived (ranked 6,976). SIMD is a measure of relative deprivation and not all people in a specific SIMD area will be equally deprived.

A preliminary analysis of offence to verdict times confirmed that these times do not follow a normal distribution and that they could not be easily transformed into a normal distribution. Therefore, non-nonparametric statistical tests were used to determine if there were differences in median journey times depending on equality factors. Kruskal-Wallis and Mann-Whitney U tests were used to determine significant differences in this analysis.The Kruskal-Wallis test was used to test for a significant difference in median journey time between three or more independent groups within the factor of interest. Then Mann-Whitney U tests were used to determine which groups within each category were significantly different from each other. A p value of <0.001 was considered to indicate a statistically significant difference. When multiple Mann-Whitney U comparisons are being made, p-values were adjusted using the Holm method to provide a more accurate assessment of the statistical significance of the results. Even when two groups have a statistically significant difference in median times, the actual time difference may not appear to be very large.

Distributions and median times are shown in box plots. A box plot can be used to show the distribution, spread, and potential outliers in the data. In this paper, the line inside the box shows the median time, the box represents the middle 50% of data (or the Interquartile Range from the first to the third quartile) and lines extend from the box to the smallest and largest values within 1.5 times the interquartile range, respectively. In this paper, outliers have been removed from the charts to allow for a clearer view of the central tendency and spread of the data. The number of case-accused in each group and the corresponding percentages of the total are shown in the tables in the Annex. The number of case-accused and the median, quartile 1 and quartile 3 offence to verdict times for each equality factor are included in the Supplementary tables.