Which Security Devices Reduce Burglary?

Abstract

This chapter examines how protection is conferred by different security device combinations. Window and door locks, in combination with security lighting, are shown to be particularly effective, demonstrating the importance of restricting access (by locking windows and doors), simulating occupancy and increasing surveillance potential (using security lighting). It is contended that different security devices have distinctive primary mechanisms – some deter (e.g. discourage an offender from selecting the property), and some thwart (e.g. physically impede entry). It is important to examine the effectiveness of specific device combinations with respect to domestic burglary with entry and attempted burglary (separately) as failure to do so risks masking any underlying (and important) changes.

Appendices

Appendix A

A.1 Introduction

The Crime Survey for England and Wales (CSEW) is a large-scale, face-to-face victimisation survey widely considered to be the most comprehensive long-term measure of crime trends available in England and Wales (Tilley and Tseloni 2016). The survey was first conducted in 1982 and from then was run approximately every 2 years until 2001, at which point it became a continuous survey.

The CSEW was, prior to April 2012, known as the British Crime Survey (BCS). From April 2012, responsibility for the survey moved from the Home Office to the Office for National Statistics (ONS). For consistency throughout the book, we refer to the survey as the CSEW.

A.2 Crime Survey for England and Wales Sample Selection

Since 2001/2002 the CSEW has used an annual rotating sample of between (approximately) 32,000 and 48,000 adults resident in England and Wales. The aim is to conduct at least 1000 core interviews in each police force area. The CSEW has sampled adults over the age of 16 since 1982. From January 2009, the survey was extended to include 10–15 year olds, although this data is not analysed within this book. Specific details regarding the sampling design can be found within TNS BMRB (2012).

A.3 Crime Survey for England and Wales Questionnaire Structure

The structure of the CSEW is relatively complex. In general, it consists of a number of core modules asked of the whole sample (e.g. socio-demographic details, experiences of the criminal justice system, etc.), a set of modules asked of different subsamples (e.g. crime prevention and security (the exact topics vary each year)), self-completion modules (e.g. offending behaviour and drug use) and, where relevant, modules concerning crime victimisation (see Appendix Table 4.6).

Appendix Table 4.6 Modules of the 2011–2012 CSEW questionnaire and subset of respondents who were asked each module

As shown in Appendix Table 4.6, the CSEW is a rich data source, collecting data regarding the characteristics (both demographic and attitudinal) of individual respondents, their household and the area in which they live as well as whether they have been a victim of crime or anti-social behaviour. In relation to household security measures, detailed information is collected from the majority of burglary victims and a randomly selected subset of the total sample (this subset comprises approximately 10,000 respondents in each sweep). Information regarding the availability of security devices at the time of the incident is gathered (via the Victimisation module) from the majority of respondents whose household was burgled. The list of devices from which respondents could choose changed considerably between the 1996 and 1998 sweeps but has remained relatively consistent since then (see Appendix Table 4.7).

Appendix Table 4.7 Household security measures over time, as measured by the CSEW (in both the Victim and Non-Victim Forms) 1992–2011/2012. Note: Adapted from Tseloni et al. (2017)

A.4 Limitations

4.5.1 A.4.1 Security Information Is Not Available for All Burglary Victims

Information about the home security devices in place at the time of the burglary is not available for a small minority of victims who reported at least three unconnected crime incidents of higher seriousness than burglary (according to standard CSEW offence classification - see Hales et al. 2000) during the reference period. By way of illustration, details about home security are not solicited from a multiple victim of three unrelated incidents of assault or robbery whose home has also been burgled. The security of the most vulnerable population is therefore unknown due to survey limitations.

4.5.2 A.4.2 Victims of Both Attempted Burglary and Burglary with Entry Are Excluded

The unit of analysis here is the household. Therefore, when a victim reported more than one burglary incident, their home security availability at the time of the first burglary (during the survey’s reference period) was retained for analysis. A minority of cases where a respondent experienced both an attempted burglary and a burglary were, however, excluded. Using the 2008/2009–2011/2012 data as an example, in a small number of cases (which make up 0.17% of the total sample, 1.6% of all burglary victims, 2.6% of victims of burglary with entry or 4.4% of victims of attempts), a respondent experienced both an attempted burglary and a burglary (separate incidents not considered to be part of a series). For the purposes of this analysis, security device availability was measured at the time of interview for non-victims and at the time of the first incident for victims. It was therefore necessary to establish when each incident happened in order to ascertain which victimisation happened first – the burglary or the attempt. Data regarding the month in which each incident happened was originally established for nine cases from the 2011/2012 sweep. Of the nine, four respondents first experienced an attempted victimisation and two burglaries with entry. With regard to the remaining three cases, both incidents happened in the same month. Therefore, we were unable to ascertain which incident happened first. As a result, because they constitute a small proportion of the total sample, cases where a respondent experienced both an attempt and a burglary with entry were excluded from this analysis.

A.5 Alternative Deter/Thwart Calculations

Using WD as an example, the population of interest in Table 4.4 was calculated by subtracting the total number of burglary with entry victims with WD from the total population with WD. Therefore, this value includes non-victims and victims of attempted burglary with WD. This is justified because here we are interested in the odds of a specific event (burglary with entry) occurring. However, one could argue the events (burglary with entry and attempted burglary) are not independent – both burglary with entry and attempted burglary households have been targeted, and therefore their security did not deter in the first place. The calculations in Appendix Tables 4.8 and 4.9 offer an alternative means of calculation (where the population includes only victims) which incorporates the events’ potential non-independence. In Appendix Table 4.8, our population is victims with particular security combinations installed in their homes. Here, we are comparing the proportion of burglary with entry victims with (for example) WD, with the proportion of attempted burglary victims with WD to calculate their relative risk. In other words, are victim households with WD at greater risk of becoming a victim of burglary with entry or attempted burglary? Note, the results are almost identical to Table 4.4.

Appendix Table 4.8 Alternative deter/thwart risk calculations (where the population selected comprises only victims with particular security combinations) (CSEW, 2008/2009–2011/2012)

Appendix Table 4.9 Alternative deter/thwart odds calculations (where the population selected comprises all victims) (CSEW, 2008/2009–2011/2012)

In Appendix Table 4.9, our population includes all victims. Here, we are comparing the odds of having each security combination for burglary with entry victims with the odds of attempted burglary victims having the same combination. In other words, are burglary with entry victims more likely (than attempted burglary victims) to have (by way of example) WD? Note that here the results are slightly different. The top two ‘thwarting’ device combinations are still window locks, door locks and security chains (WDS) followed by window locks and security chains (WS). However, the results in Appendix Table 4.9 suggest there are a larger number of ‘thwarting’ device combinations. All ‘thwarting’ combinations (bar one, WS) include door locks which is consistent with our expectations outlined in Table 4.3. Although Appendix Table 4.9 presents a larger number of thwarting combinations, the results are consistent (across Table 4.4 and Appendix Tables 4.8 and 4.9) in that window locks, door locks and security chains (in various combinations) are deemed to thwart.

A.6 More Information

For more details regarding CSEW methodology, questionnaires and topics covered, see Hough and Maxfield (2007), Flatley (2014) and the various CSEW Technical Reports (TNS BMRB 2012). For more information on crime statistics more generally, please see the ONS (2018b) user guide.