6. VIOLENT CRIME INDICATOR
TABLE 1 – INDICATOR DESCRIPTION
| Information component | Pg 4 Health Summary – Indicator No 6 |
| Subject category / domain(s) | Our communities |
| Indicator name (* Indicator title in health profile) | Recorded crimes of violence against the person (“Violent crime”) |
| PHO with lead responsibility | SWPHO |
| Date of PHO dataset creation | Jan 2007 |
| Indicator definition | Recorded violence against the person offences, Crude rate per 1,000 population, All ages, 2004/05-2005/06, Persons |
| Geography | England, GOR, Local Authority: Counties, County Districts, Metropolitan County Districts, Unitary Authorities, London Boroughs |
| Timeliness | The indicator presented in Health Profiles is routinely updated annually (usually in July). |
| Rationale:What this indicator purports to measure | Level of reported violence against the person offences in an area |
| Rationale:Public Health Importance | The links between crime and health are complex (as outlined in the London Health Commission report http://www.londonshealth.gov.uk/pdf/lhs/crime.pdf) but it is likely that crime is a determinant and a consequence of health. Research undertaken by the Home Office and a number of other organisations suggests that there is a relationship between violent crime and alcohol (https://www.fph.org.uk/policy_communication/downloads/ publications/briefing_statements/alcohol%20and%20violence%20-%20final%20pdf.pdf). Violent crime may result in temporary or permanent disability and in some cases death. Some victims of crime may suffer psychological distress and subsequent mental health problems. Crime and fear of crime can also alter people’s lifestyles and impact on their physical and psychological health (http://www.manchester.gov.uk/health/jhu/intelligence/reports/crime.htm ). Collectively, these consequences represent a burden to the healthcare services. This indicator specifically measures recorded ‘violence against the person’, the largest component of total ‘violent crime’ (which also includes robbery and sexual offences). |
| Rationale: Purpose behind the inclusion of the indicator | To help target policing and crime prevention resources and to reduce the incidence of violent crime. |
| Rationale:Policy relevance | Targets included in the Treasury’s Spending Review provide the basis for policy priorities. In 2002 the spending review included targets to reduce crime and the fear of crime and to reduce the gap between those Crime and Disorder Reduction Partnerships experiencing the highest crime and other areas. |
| Interpretation: What a high / low level of indicator value means | A high indicator value (red circle in health summary chart) represents a statistically significant higher rate of reported violent crime when compared to the England average value. A low indicator value (amber circle in health summary chart) represents a statistically significant lower rate of reported violent crime when compared to the England value.However, it should be noted that high values reflect higher numbers of crimes recorded by the police. This may be a result of higher underlying incidence of violent offences, a greater proportion of incidents being reported to the police, or as a result of policing practice. The converse is true for low values of the indicator. |
| Interpretation: Potential for error due to type of measurement method | This indicator omits violent offences which are not reported to the police. It is susceptible to changes in police crime reporting procedures. |
| Interpretation: Potential for error due to bias and confounding | The level and intensity of police service provision will affect rates of recorded violent crime offences, i.e. the higher the level of policing, the more likely it is that recorded crime figures will be elevated. Caution needs to be taken when considering crime rates in areas with low resident populations (e.g. City of London) in which violent crimes are carried out by non-residents. |
| Confidence Intervals: Definition and purpose | A confidence interval is a range of values that is normally used to describe the uncertainty around a point estimate of a quantity, for example, a mortality rate. This uncertainty arises as factors influencing the indicator are subject to chance occurrences that are inherent in the world around us. These occurrences result in random fluctuations in the indicator value between different areas and time periods. In the case of indicators based on a sample of the population, uncertainty also arises from random differences between the sample and the population itself.The stated value should therefore be considered as only an estimate of the true or ‘underlying’ value. Confidence intervals quantify the uncertainty in this estimate and, generally speaking, describe how much different the point estimate could have been if the underlying conditions stayed the same, but chance had led to a different set of data. The wider is the confidence interval the greater is the uncertainty in the estimate.Confidence intervals are given with a stated probability level. In Health Profiles 2007 this is 95%, and so we say that there is a 95% probability that the interval covers the true value. The use of 95% is arbitrary but is conventional practice in medicine and public health. The confidence intervals have also been used to make comparisons against the national value. For this purpose the national value has been treated as an exact reference value rather than as an estimate and, under these conditions, the interval can be used to test whether the value is statistically significantly different to the national. If the interval includes the national value, the difference is not statistically significant and the value is shown on the health summary chart with a white symbol. If the interval does not include the national value, the difference is statistically significant and the value is shown on the health summary chart with a red or amber symbol depending on whether it is worse or better than the national value respectively. |
TABLE 2 – INDICATOR SPECIFICATION
| Indicator definition: Variable | Recorded violence against the person offences |
| Indicator definition: Statistic | Crude rate |
| Indicator definition: Gender | Persons |
| Indicator definition: age group | All ages |
| Indicator definition: period | Numerator financial years 2004/05 – 2005/06. Denominator mid-2004 |
| Indicator definition: scale | Per 1,000 population |
| Geography: geographies available for this indicator from other providers | England, GOR, Local Authority: Counties, County Districts, Metropolitan County Districts, Unitary Authorities, London BoroughsAnnual rates and numerators available for these geographies from www.homeoffice.gov.uk |
| Dimensions of inequality: subgroup analyses of this dataset available from other providers | None available. |
| Data extraction: Source | Home Office |
| Data extraction: source URL | http://www.homeoffice.gov.uk/rds/crimeew0506.html |
| Data extraction: date | Data extracted from source as at: 01/05/2006 |
| Numerator: definition | Annual count of recorded ‘violence against the person’ offences in the respective financial years.Violence against the person comprises the following offences:Murder, attempted murder, threat or conspiracy to murder, manslaughter, infanticide, child destruction, causing death by Dangerous or careless driving, causing or allowing death of a child or vulnerable person, causing death by driving, wounding or other acts endangering life, endangering a railway passenger, endangering life at sea, other wounding, possession of weapons, harassment, racially or religiously aggravated other wounding, racially or religiously aggravated harassment, cruelty to and neglect of children, abandoning child under two years, child abduction, procuring illegal abortion, concealment of birth, causing death by aggravated vehicle taking, assault on a constable, common assault, racially or religiously aggravated common assault.Please see the following for more details: http://www.homeoffice.gov.uk/rds/pdfs07/countviolence07.pdf |
| Numerator: source | Home Office |
| Denominator: definition | 2001 Census based mid-year population estimate for the mid-point year (2004).Data are based on the latest revisions of ONS mid-year population estimates for the respective year, current as at 24 August 2006. |
| Denominator: source | Office for National Statistics (ONS). |
| Data quality: Accuracy and completeness | Coverage is complete. Historically there have been differences between police forces in procedures for recording, collecting and collating offence data. In April 2002, the National Crime Recording Standard (NCRS) was introduced to ensure greater consistency between forces in recording crime.As a result of the introduction of the NCRS, the recorded number of violence against the person offences increased by 23% in 2002/03.(http://www.crimestatistics.org.uk/output/Page107.asp).Home Office research (http://www.homeoffice.gov.uk/rds/pdfs06/hosb1206.pdf) suggests that about 45% of violent crimes are reported to the police, with 68% of these being officially recorded as a crime.The Home Office provides specific counting rules regarding the counting and classification of violence against the person offences recorded by Police Forces in England and Wales (http://www.homeoffice.gov.uk/rds/countrules.html). |
TABLE 3 – INDICATOR TECHNICAL METHODS
| Numerator: extraction | Downloaded from www.homeoffice.gov.uk |
| Numerator: aggregation /allocation | Area where offence took place allocated by police using records with attached postcodes. |
| Numerator data caveats | Changes in recording practice, boundary alterations and case definition make historical analysis of data problematic. In 1998, changes to the Home Office Counting rules had a significant impact on violent crime; the numbers of such crimes increasing by 83% as a result of the 1998 changes. In particular police recorded crime has been inflated over the last few years by changes in recording practice (particularly marked since the introduction of the National Crime Recording Standard (NCRS) in April 2002), increased reporting by the public and increased police activity. The British Crime Survey is not susceptible to changes in recording practice and is considered the more reliable indicator. Although historical analysis of BCS estimates is possible, data are not available at District level. |
| Denominator data caveats | Ideally, the denominator should reflect all people at risk of violent crime in the area, including visiting and or migratory persons. This data is not available and resident data has been used as a proxy.The use of resident population as a denominator is a proxy measure for population exposure and is consistent with how this indicator is presented elsewhere. |
| Methods used to calculate indicator value | Calculation of the numerator: Calculated as an annual of the number of the offences reported in 2004/05 to 2005/06. Denominator count: Mid-2004 population estimates (all ages). The numerator was then divided by the denominator; the resulting value was then multiplied by 1000 to give a crude rate per 1000 population. |
| Small Populations: How Isles of Scilly and City of London populations have been dealt with | Data for the Isles of Scilly and for the City of London have not been included in the Health Profiles but have been included in the data published by the Home Office. |
| Disclosure Control | Not applicable as no counts less than 5. |
| Confidence Intervals calculation method | The confidence intervals for these crude rates were constructed using the following formula that relates the chi-square and Poisson distributions: 
where LL and UL are lower and upper confidence limits respectively for the rate as d events per unit time exposed, χ² ν,a is the (100*α)th chi-square centile with ν degrees of freedom, and d is the number of observed events (e.g. serious injuries and deaths). Reference:Dobson AJ, Kuulasmaa K, Eberle E, Scherer J. Confidence intervals for weighted sums of Poisson parameters. Statistics in Medicine 1991;10:457-462. |
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