Scottish Crime and Justice Survey 2017/18: main findings

1. Introduction and background to the SCJS

What is the SCJS and what purpose does it serve?

The Scottish Crime and Justice Survey (SCJS) is a large-scale social survey which asks people about their experiences and perceptions of crime. It is completed face-to-face in the homes of respondents, with sections on more sensitive topics completed by the respondent themselves using the interviewer’s laptop or tablet as part of the main interview.

Crime and victimisation surveys have been carried out in Scotland since the early 1980s; however, this report presents the results for the seventh SCJS, with interviews conducted between April 2017 and May 2018. The 2017/18 survey is based on around 5,500 face-to-face interviews with adults (aged 16 or over) living in private households in Scotland.

The main aims of the SCJS are to:

• Enable the Scottish population to tell us about their experiences of, and attitudes to, a range of issues related to crime, policing and the justice system; including crime not reported to the police;
• Provide a valid and reliable measure of adults' experience of crime, including services provided to victims of crime;
• Examine trends, over time, in the number and nature of crimes in Scotland, providing a complementary measure of crime to police recorded crime statistics;
• Examine the varying risk and characteristics of crime for different groups of adults in the population.

The findings from the SCJS are used by policy makers across the public sector in Scotland to help understand the nature of crime in Scotland, target resources and monitor the impact of initiatives to target crime. The results of this survey provide evidence to inform national outcomes and justice outcomes.

What do I need to know when reading this report?

Detailed information about the history, design and methodology of SCJS is provided in the accompanying Technical Report to help you understand the strengths and limitations of the survey’s results. Annex E also provides guidance on how to interpret charts and tables contained in this report. The sections below provide summary information on: the background to the SCJS, the reliability of survey estimates and how uncertainty around results is explained, as well as an overview of the content of this report and other SCJS supporting outputs.

Who is included and what does the SCJS cover?

The SCJS does not aim to provide an absolute estimate for all crime and has some notable exclusions.

The SCJS is a survey of adults living in private residential households (including private and social rented housing) and therefore does not provide information on crimes against adults living in other circumstances (for example tourists and those living in institutions or communal residences, such as prisons or hospitals, military bases and student accommodation). The survey also excludes persons under the age of 16 and crimes against businesses. Further details on the sampling approach is outlined in the accompanying Technical Report.

The SCJS is primarily a victimisation survey which captures information on adults’ experiences of violent crime and property crime, including those not reported to the police. However, it does not capture data on all crimes – for example crimes without a direct victim (e.g. speeding and drug possession), and some high harm but relatively lower-volume offences, such as homicide and sexual offences, which are not included in the main estimates. Experiences of sexual offences are collected in the self-completion section and reported separately (although are contained within this report).

Throughout the report, the term 'crime' is used to refer to any in-scope incident recorded by the survey, occurring during the interview reference period and in Scotland, in which the respondent or their household as a whole was the victim.

The survey also explores perceptions of the police, justice system and safety in Scotland.

How is the survey delivered?

The design of the 2017/18 SCJS was broadly similar to the design of the SCJS from 2008/09 onwards. Therefore, this report generally compares the latest findings to those in 2008/09 and the last SCJS in 2016/17 when examining changes over time.

Other summary points to note on the methodology are outlined below.

• Survey frequency: Since 2008/09 the frequency of the SCJS has varied a little. In 2016/17, the SCJS reverted to being conducted on an annual basis. The 2017/18 SCJS is the latest annual survey.
• Sample: the sample is designed to be representative of all private residential households across Scotland. A systematic random selection of private residential addresses across Scotland was produced from the Royal Mail Postcode Address File (PAF) and allocated in batches to interviewers. Interviewers called at each address and then selected one adult (aged 16 or over) at random from the household members for interview.
• Questionnaire: the questionnaire consists of a modular design completed by the interviewer using Computer-Assisted Personal Interviewing (CAPI) and a self-completion section covering sensitive crimes using Computer-Assisted Self Interviewing (CASI). Annex C gives an overview of the questionnaire structure and general topics, and the most recent questionnaire is available on the SCJS website.
• Fieldwork: interviews were conducted on a rolling basis between April 2017 and May 2018, with roughly an equal number of interviews conducted across most months. Challenges in fieldwork delivery were experienced and as a result, the fieldwork period was extended into May to increase the achieved sample size.
• Interviews: 5,475 face-to-face interviews were conducted in respondents' homes by professional interviewers from an original target of 6,000. The achieved response rate was 62.4%, against a target of 68%. This was similar to the achieved response rate in 2014/15 (63.8%) and 2016/17 (63.2%), but lower than the 67.7% achieved in 2012/13.
• Interview Length: Interviews lasted on average around 40 minutes, though there was variation in interview length, depending on the respondent's reported experience.
• Time period covered: respondents were asked about incidents experienced in the 12 months prior to the month of interview (the reference period). The time period covered by the data included in this report extends over 25 months (April 2016 to May 2018) so is not directly comparable with any calendar year.
• Weighting: the results obtained were weighted to correct for the unequal probability of selection for interview caused by the sample design and for differences in the level of response among groups of individuals.

Further information about the design and methodology is contained in the accompanying Technical Report.

How reliable are SCJS results?

The SCJS gathers information from a sample rather than from the whole population and, although the sample is designed carefully, survey results are always estimates, not precise figures. This means that the results are subject to a margin of error which can have an impact on how changes in the numbers should be interpreted, especially in the short-term.

To indicate the extent of uncertainty, this report presents key results on the extent and prevalence of crime with best estimates and also lower and upper estimates. The best estimate is the mean figure drawn from the sample. The lower and upper estimates are for the 95% confidence interval. The majority of the analysis in the report however focuses on best estimates.

Because of sampling variation, changes in reported estimates between survey years or between population subgroups may occur by chance. We therefore use standard statistical tests to examine whether differences are likely to be due to chance. Only differences that are statistically significant at the 95% significance level are described as differences or changes within this report.

Where no statistically significant change has been found between two estimates, this has been described as showing ‘no change’ (or equivalent). The presentation of uncertainty and change in this report reflect best practice guidance produced by the Government Statistical Service (GSS)^[2].

Uncertainty can be particularly high around some estimates, often where experiences are rare. We assessed this for crime incidence figures in this report by computing the relative standard error around the results (RSE), which is equal to the standard error of a survey estimate divided by the survey estimate multiplied by 100. We have flagged results which have RSE values > 20% and we recommend that such results are used with caution.

What findings are included in this report and where can I access additional results?

The report is split into sections which focus on presenting data for the majority of topics covered by the survey questionnaire including: the extent, prevalence and nature of crime in Scotland; perceptions of the police and justice system; and consideration of how evidence from the SCJS compares to and complements police recorded crime statistics in Scotland. The report does not include in-depth, multivariate statistical analysis that would explore the more complex underlying relationships within the data.

This report contains a range of demonstration tables and charts within the body of each chapter. Further information on how to interpret charts, tables and data presented in this report is provided in Annex E. Many of these tables and charts include breakdowns by respondent characteristics such as age, gender, deprivation, rural/urban and victim status. Further detail on many of these tables, for example with additional breakdowns, and full time series results, are provided in the data tables presented in Annex A.

We have also released a more comprehensive set of SCJS Data tables alongside this report which present further breakdowns of results, from a wide range of survey questions, by geographic, demographic, attitudinal or experiential characteristics of respondents.

The raw survey data files and survey documentation will be available soon after publication of this report from the UK Data Service.

Data collected by the self-completion element of the SCJS (on drug use, partner abuse, and sexual victimisation and stalking) is collated over two survey sweeps and published biennially. This report also therefore contains key findings on each of the self-completion topics from SCJS interviews conducted in 2016/17 and 2017/18 (described where relevant as 2016/18). Previously these modules have been reported in standalone topic reports. Supporting data tables have also been published to provide additional findings from these questionnaire sections.

SCJS results provided to Police Division level are available biennially (as they have been since 2012/13), with two sweeps of data combined to increase the sample size and precision around results with effect from 2016/17. Therefore, key results at Police Division level covering the period 2016/17 – 2017/18 have also been released alongside this report. Findings released include perceptions of the police, as well as wider SCJS results such as victimisation rates, within each Division. They are most easily accessed in the recently launched SCJS interactive data tool which has been developed to present these results in a user-friendly manner. This enables divisional results to be compared over time, as well as against each other and the national average for each sweep^[3][4]. Further information on the SCJS reporting structure is available on the SCJS website.

How can I find out more about the SCJS?

Scottish Crime and Justice Survey - User Engagement

The SCJS is used in multiple ways and by multiple users across government, public services, academia and third sector. Engaging effectively with users is important in ensuring that the SCJS meets the needs of users.

If you want to find out more about work relating to the Scottish Crime and Justice Survey or any other facet of the work of the Scottish Government Statistics Group, you can through the following ways:

SCJS User Group

The SCJS team have established a user group to ensure that user engagement is an on-going part of each survey cycle. Members are drawn from government, academia, the justice system and third sector. The user group is an essential way to ensure that the survey remains relevant and able to respond to changing needs. If you would like to become involved in the user group, please contact us.

ScotStat

Register with ScotStat: a network for users and providers of Scottish Official statistics. It aims to improve communication amongst those interested in particular statistics and facilitate the setting up of working groups on specific statistical issues.