Recorded Crime in Scotland, 2013-14

Annex 3: Recorded Crime: Comparability of Police Scotland and Legacy Force Data

4.26 With the establishment of Police Scotland, a new IT system, Scottish Operational and Management Information System (ScOMIS), was developed. This collates crime reports from across the variety of systems used by the eight legacy police forces into one central information management system and supplies the Scottish Government with recorded crime data. Previously, the Scottish Government collected recorded crime data from the eight legacy police forces, who in turn had extracted the data from their own systems.

There were two aims to the report:

• To investigate the comparability of ScOMIS data and legacy force data; and
• Check the quality of recorded crime data supplied by the police.

The Technical report on the comparability of recorded crime data report should be read alongside the User Guide to Recorded Crime Statistics in Scotland and this bulletin, as these provide context and background information on recorded crime data.

To enable a full check of whether data extracted from ScOMIS were comparable with legacy force data, ScOMIS was populated with data for 2008-09 onwards. These data were then compared with the data previously submitted by the legacy forces. To be as thorough as possible, this was done at local authority level for all 470 crime codes over the five year period between 2008‑09 and 2012-13. Any differences were then investigated by Police Scotland and rectified if appropriate.

The majority of differences between the data sources were due to the fact that a snapshot of historical data was being compared to a more up-to-date snapshot of data. There were two reasons why the recorded crime data may have changed in the time period between two snapshots:

• Changes made as a result of on-going police investigation. This includes the reclassification of crimes and offences and no criming, i.e. where it is determined by the police that no crime actually took place. It is not possible to know the extent to which differences between ScOMIS and previous data are due to these types of changes - Section 14 of the User Guide to Recorded Crime in Scotland.
• Changes to crime codes. A number of changes have been made to crime codes over the period 2008-09 to 2012-13, as well as changes to how particular incidents are recorded by the police. These changes do not affect the accuracy or comparability of recorded crime data previously published by the Scottish Government.

A number of specific issues with the data were identified:

• Issues relating to ScOMIS. Two issues were discovered with the way ScOMIS was extracting data from the legacy force systems. Both of these issues have since been rectified by Police Scotland.
• Issues relating to legacy force data. The issues identified with legacy forces' data collections include recording errors as well as specific data errors on a small number of crime codes. The majority of errors identified in this section will be corrected with the publication of the Recorded Crime in Scotland, 2013-14 bulletin. However, the overall comparability of Group 6 has been affected by these errors.
• Changes in reporting practices. There were a large number queries raised with Police Scotland regarding Group 7 offences. They related to both the comparability and the quality of the data. It was determined, that with the establishment of Police Scotland there has been a standardisation of the reporting practices for what data should and should not be included in data returns to the Scottish Government. These included offences recorded as a result of the Scottish Safety Camera Programme, offences arising from the DVLA issuing tickets, offences resulting from the Vehicle Defect Rectification Scheme and offences recorded as a result of the Driver and Vehicle Standards Agency. With the standardisation in reporting practices the overall comparability of Group 7 has been affected. This is true for comparing the data post and pre reform as well as when comparing the data pre reform.

In terms of comparability, the Scottish Government are satisfied that crime data, Groups 1 to 5, are comparable pre and post reform. This means there will be no break in the time series for this data.

However the overall comparability for offences data, Groups 6 and 7, has been affected by some of the issues relating to legacy force data and changes in recording practices. For Group 6, all crime codes are fully comparable from 2008-09 onwards and overall comparisons for Group 6 should only be made for 2008‑09 onwards. There are greater comparability issues for Group 7 and overall comparisons for Group 7 should not be made prior to 2013-14. This is discussed fully in Section 7 of the Technical report on the comparability of recorded crime data.

Overall, the Scottish Government are confident that ScOMIS can provide data which are accurate and reliable for inclusion in the Recorded Crime in Scotland statistical bulletin series.

The full version of the report can be accessed here: http://www.scotland.gov.uk/Topics/Statistics/Browse/Crime-Justice/PubRecordedCrime/TechnicalReport