Guidance

Knife and Offensive Weapon Sentencing Statistics Technical Guide

Updated 16 May 2024

Applies to England and Wales

This page provides more detail on the statistics presented in the Knife and Offensive Weapon Sentencing Statistics publications which provide information on knife and offensive weapon offences. Unless the offences are separately specified this includes:

• Possession of an article with a blade or point in a public place or on school premises.
• Possession of an offensive weapon without lawful authority or reasonable excuse in a public place or on school premises.
• Offences involving threatening with a knife or offensive weapon in a public place or on school premises (introduced on 3rd December 2012 this is an aggravated form of possession offence which occurs when an offender in possession of a knife or offensive weapon uses it to threaten and endanger others).

The Technical Guide (Chapter 1) is intended to be used as a guide to concepts and definitions. It also provides information on key events and policy changes that may be relevant to the publication’s findings, as well as technical guidance on the methodologies employed for collecting, presenting and (where relevant) estimating the statistics laid out in the publication.

The Data Quality Statement (Chapter 2) describes how the publication meets the different quality aspects set out in the National Statistics Code of Practice.

1. Technical Guide

1.1 Key events

Key events that might be expected to affect the statistics in this bulletin include:

• On 21 May 2008, the Court of Appeal issued the judgment in Povey^{[footnote 1]} . The Court drew attention to an escalation of possession of knife and offensive weapon offences and recommended that magistrates should normally sentence those convicted of such offences at the top end of the appropriate range. The Court also drew attention to the importance of sentencing courts ensuring that sentencing for these offences takes account of the need to reduce crime, including by deterrence, and protect the public.
• The Sentencing Guidelines Council (later replaced by the Sentencing Council) subsequently updated the Magistrates’ Court Sentencing Guidelines on possession of a weapon, which took effect on 4 August 2008. The update set out the impact of the Court of Appeal judgment and clarified that the starting point for the lowest level of knife possession amongst adults should be close to 12 weeks’ custody. This applies in cases where a first-time adult offender pleads not guilty to possession of a knife in non-dangerous circumstances. A guilty plea would attract a discount in the normal way, as would any personal mitigation, and could take the sentence below the custody threshold.
• From 3 December 2012, offences of aggravated knife, or offensive weapon, possession came into force. Anyone aged 16 or over who uses a knife or offensive weapon to threaten and endanger others in a public place or on school premises will face a minimum custodial sentence, unless the court considers there to be particular circumstances which would make it unjust to do so.
• In November 2013 revised guidance on cautions was issued. The guidance made it clear that simple cautions should not be given for possession of a knife, and other serious either way offences, unless their issue was signed off by at least an Inspector.
• In April 2014, the Court of Appeal issued the judgment in Monterio^{[footnote 2]} that said the Youth Courts should maintain the sharp focus called for in Povey^{[footnote 1]} by imposing appropriate sentences that will contribute to preventing further offending and to a reduction in knife crime.
• Statutory restrictions around the use of cautions, including their use for possession of a knife or offensive weapon, came into force in April 2015. These restrictions state that a constable must not give a caution for the relevant offences, if in the two years before the offence the offender was convicted of or cautioned for a similar offence.
• On 17 July 2015 a minimum custodial sentence for those aged 16 or over who are convicted of a second or subsequent offence of possessing an offensive weapon or bladed article came into force. The minimum custodial sentence is six months for those aged 18 or over and a four-month detention and training order for 16- and 17-year olds.
• On 1 December 2020, the minimum sentencing provisions, including for offences relating to threatening with an offensive weapon or a bladed article and a repeat offence involving an offensive weapon or a bladed article, were consolidated into the Sentencing Code by the Sentencing Act 2020.
• Section 52 of the Offensive Weapons Act 2019 (2019 Act) introduced the offence of threatening with an offensive weapon in a private place, however this provision is not yet in force. This is a standalone offence with a maximum penalty of 4 years imprisonment. The minimum sentence does not apply.
• The 2019 Act also made provision (which has since been consolidated by the Sentencing Act 2020 but has not yet been commenced) for corrosive substances to be included in the minimum sentence for repeat offences involving offensive weapons or bladed articles under section 315 of the Sentencing Code. This will influence the statistics once commenced.
• The 2019 Act also introduced Knife Crime Prevention Orders (KCPOs), which are civil orders that can be imposed on anyone over the age of 12 who the police believe is regularly carrying a knife, or upon conviction of a knife related offence. Anyone who breaches a KCPO faces a two-year custodial sentence. KCPOs are intended to be preventative and are currently being piloted across the whole of the Metropolitan Area.

1.2 Sentencing Act 2020 – Minimum sentences for threatening offences and repeat knife and offensive weapon possession offences

The Q2 2021 edition of the knife possession sentencing statistics included additional tables; 7a, 8a and 9a, presented alongside tables 7, 8 and 9. Tables 7a, 8a and 9a related to repeat possession offences under Section 315 of the Sentencing Act 2020 (formerly Section 28 of the Criminal Justice and Courts Act 2015) and exclude cautions, both when considering an individual’s offence history and as an outcome. They also separated cases committed to the crown court for sentencing from the “other” disposal category. These tables now replace 7, 8 and 9 for the Q3 2021 and future editions of the publication.

On 17 July 2015 a minimum sentence for repeat knife or offensive weapon possession came into force.

• Section 315 of the Sentencing Code provides for a minimum custodial sentence for those aged 16 and over convicted of a second or subsequent offence of possession of a bladed article or offensive weapon in a public place or on education premises.
• The minimum sentence is at least six months of custody for adults, and at least a four-month Detention and Training Order (DTO) for 16- and 17-year olds.
• The courts will consider aggravating and mitigating factors when determining the sentence, following relevant sentencing guidelines.
• Currently, the minimum sentence only applies on conviction of a second or subsequent offence where that offence was committed on or after 17 July 2015. There is no time limit on the previous conviction, though it must be a relevant offence .
• A previous conviction for threatening with a knife or offensive weapon also counts as a ‘first strike’.
• A conviction for an equivalent service offence counts as a ‘first strike’ for the purposes of the minimum sentence. Convictions in other parts of the United Kingdom are also relevant, as are convictions in the European Union in particular circumstances.
• The court must impose the minimum sentence unless there are particular circumstances which relate to the offence, the previous offence(s), or the offender which would make the imposition of the minimum sentence unjust in all the circumstances.

Some children may not receive a custodial sentence. This is because a 4-month DTO is the minimum custodial sentence available for this offence and if the court applies a reduction in sentence for a guilty plea or for time spent on remand or bail (which is subject to a qualifying curfew condition and an electronic monitoring condition) then a non-custodial sentence will result.

In the case of adults, where the court imposes the minimum sentence this can be reduced by up to 20% for an early guilty plea, resulting in a sentence of 4.8 months. If the sentence is below 2 years, the court may decide to impose a suspended sentence instead. This would mean that the custodial threshold has been met, but, after considering all the circumstances of the case, the court considered a suspended sentence to be more appropriate than immediate custody. As part of the suspended sentence, the court may also impose requirements which are designed to help address offending behaviour. If the suspended sentence is breached, the offender will be returned to court, and, if the breach is proven, the court can activate the custodial sentence.

Equivalently the Sentencing Act 2020 also sets minimum sentences for those convicted of threatening offences. The minimum sentences are the same as for repeat possession offences but, for threatening offences, can be either a first or a subsequent offence. Analysis of cases dealt with under this part of the legislation was introduced in the Q4 2022 publication in tables 7a, 8a and 9a.

1.3 Data quality and sources

Tables 1 to 9

The statistics presented in tables 1 to 9 in this bulletin, the interactive pivot table tool and the Sankey diagram, are drawn from an extract of data held on the PNC^{[footnote 3]} approximately four months after the period the publication covers.

The PNC is a large administrative database containing information about police cautions and court convictions held by individual offenders in England and Wales. The PNC is regularly updated as new information about individuals becomes available. For example, an offender with previous convictions may have recently been charged with another offence, appeared in court against this charge and then been subsequently convicted of this offence. This information would then be updated accordingly against that individual’s record in the PNC.

As these updates involve manual data entry alongside more automated systems, there can be delays in the database becoming updated with the latest information about an offender’s convictions. As such, the number of cautions/convictions recorded in the PNC extract for knife or offensive weapon offences, for the most recent quarter included in this bulletin, is likely to be lower than the actual number of cautions/convictions given in the period.

In addition, the different disposals recorded in the PNC extract for knife or offensive weapon offences in recent quarters are also subject to some change. This is partly due to the delays in updating recent court outcomes on the PNC, but is also due to the fact that, for some individuals who have been convicted of a knife or offensive weapon offence in a magistrate’s court during the quarter, information about the disposal they received is not yet available as the case has been passed to the Crown Court for sentencing at a later date. These cases will be updated when information about the final sentence given for the offence becomes available. This was previously taken into account using the estimation methodology described in Technical Guide Annex 1 but, after increasing the time lag between the period and publication to around 5 months, this estimation is no longer used.

Prison population data

Prison population data used to be presented in this report and, where relevant, may be presented in future editions of the report.

Prison population data presented in this bulletin are drawn from the prison National Offender Management Information System (p-NOMIS). Whilst the PNC provides details on offences committed and sentences given to offenders, snapshot data taken from p-NOMIS provide information on the number of offenders currently serving custodial sentences. The figures presented in this bulletin do not include offenders who have been recalled to custody after being released on licence.

The prison population data presented in this bulletin for periods before 30 June 2015 represent those serving a sentence for a “possession of an offensive weapon” offence. This category includes knives but can also include other dangerous weapons (excluding firearms). Since 30 June 2015, due to improvements in the system used for processing data extracted from p-NOMIS, more detailed information about the prison population has been available. This means that the data now show the numbers serving a sentence for offences relating to the possession of an offensive weapon, possession of an article with a blade or point, or threatening with an offensive weapon.

Due to technical problems relating to the supply of data for statistical purposes it has not been possible to provide data relating to the prison population for specific offence types from July 2009 to March 2010.

1.4 Other statistical releases relating to knives and sharp objects

Other government departments also release statistics relating to knives and sharp objects. Below are some links and brief outlines of other available sources.

• The Home Office provide a guidance document regarding the law for knives and offensive weapons.

• The Office for National Statistics also publish statistics on offences involving knives, offensive weapons and sharp instruments. This is contained within the Crime in England and Wales Statistical bulletins - Office for National Statistics (ons.gov.uk) and has a section called “Offences involving knives and sharp instruments”.

• The MoJ publishes information on criminal court timeliness (Table T6). These statistics relate to how quickly criminal cases are dealt with in magistrates’ courts and the Crown Court in England and Wales.

• The year ending December editions of the quarterly Criminal Justice Statistics publication issued by the MoJ include an open data tool (Outcomes by offence) giving a breakdown of court cases and outcomes by offence and this includes breakdowns for knife and offensive weapon offences.

• The Department for Health release hospital admission data for assaults on an ad hoc basis. Within this data there is a category for X99-Assault by sharp object. You can access this by clicking the link, then opening the latest Hospital Admitted Patient Care Activity page and downloading the “External causes” spreadsheet.

• The National Offender Management Service (NOMS) publishes information on assaults and other incidents in prisons, including those involving knives and sharp objects, in their Safety in Custody publication. The bulletin is released quarterly, with additional tables published on an annual basis.

1.5 Glossary

Adult:

An offender aged 18 or over.

Caution:

A warning that is given to adult offenders who admit guilt and agree to be cautioned. They are issued on the instructions of a senior police officer where there is sufficient evidence for a conviction and it is not considered to be in the public interest to institute criminal proceedings.

Child:

An offender between the ages of 10 and 17.

Community sentence:

A non-custodial sentence which is served in the community over a period of time and can involve the compliance of the offender with one or more ‘requirements’ (things the offender must or must not do while serving their sentence). For juveniles the community sentences used are Referral Order, Reparation Order and Youth Rehabilitation Order (YRO), while for adults it is the Community Order.

Potential requirements associated with a community sentence include: supervision; unpaid work; specified or prohibited activities; accredited programmes; curfew; exclusion from or residence at a particular address; mental health, drug or alcohol treatment (with offender consent); and attendance at a centre (for under 25s). The requirements aim to punish offenders and change offenders’ behaviour so they don’t commit crime in the future, and to make amends to the victim of the crime or the local community.

England and Wales:

Total figures for England and Wales now include all police forces in England and Wales and the British Transport Police (BTP).The Home Office is responsible for policing the 43 police forces in England and Wales. Other authorities also prosecute offenders such as: the Department for Work and Pensions (DWP), HM Revenue and Customs (HMRC) and the Ministry of Defence (MOD).

Immediate custody:

Unsuspended imprisonment for adults aged 21 or over and detention in a young offender institution for those aged 18 to 20. The maximum sentence available for adult knife or offensive weapon offenders is 4 years. Juveniles aged 12 to 17 may receive a detention and training order of 4, 6, 8, 10,12, 18 or 24 months.

Knife or offensive weapon offences:

In this bulletin where reference is made to knife or offensive weapon offences, unless they are separately specified, this refers to:

• Possession of an article with a blade or point on school premises or in a public place.
• Possession of an offensive weapon without lawful authority or reasonable excuse on school premises or in a public place.
• Threatening with a knife or offensive weapon on school premises or in a public place.

Offensive weapon:

Any article made or adapted for use for causing injury to a person, or intended by the person having it with him for such. Examples include: a swordstick, a hollow walking-stick or cane containing a blade.

Reprimand and warning:

Issued to juvenile first-time offenders for minor offences. Reprimand and warnings for juveniles are the equivalent of cautions for adults. These were replaced by youth cautions on April 8th 2013.

Suspended Sentence:

A custodial sentence of 6 months or less in magistrate’s courts and 2 years or less in the Crown Court, suspended for a period ranging from six months to two years available for adults only.

Youth cautions:

Introduced on April 8th 2013. They are formal out-of-court disposals for young offenders (aged 10 to 17) and intended to allow a more flexible response to offending than the preceding Final Warning Scheme. These now replace reprimands and warnings. Guidance on youth cautions can be found at https://www.gov.uk/government/publications/out-of-court-disposals.

1.6 Technical guide Annex 1 - Estimation methodology

MOJ removed the estimation methodology from the Q4 2020 publication. This was in line with a change to the publication schedule bringing this bulletin in line with other sentencing statistics published by the Ministry of Justice (MoJ)^{[footnote 4]}, which have a five-month delay instead of three. This delay allows more time for cases to pass through the criminal justice system. The detail of the previous estimation methodology is maintained in this guide for completeness and is available below:

During the development of the October to December (Q4) 2013 bulletin, it was noted that the latest disposal figures recorded on the Police National Computer (PNC)^{[footnote 3]} for Q4 2012 were significantly higher than those published at the time. The main reason for this is that cases can take some time to pass through the criminal justice system. This means that the ‘actual’ number of cases dealt with in a quarter may not be finally recorded until up to a year later.

Further analysis revealed that the extent of this increase tended to be stable over time. This enabled us to develop a methodology to estimate the number of each category of disposals given for two types of knife or offensive weapon possession offences:

• Possession offences of having an article with a blade or point in a public place or on school premises.
• Possession of offensive weapon without lawful authority or reasonable excuse in a public place or on school premises.

To estimate a statistic, the method looks at the average change between the observed and actual figures for that statistic over the previous 8 quarters. This average change is used to create a grossing factor, which is then applied to the current observed figure. These estimated figures are presented in the data tables where actual data is not yet available. Estimated figures are highlighted in all tables and charts presented in the bulletin.

As an example of the workings and accuracy of this estimation process, the Q4 2011 figures for possession of a knife or offensive weapon were first published in March 2012. We now know that there were an additional 30 more disposals given for possession offences in the quarter than originally suggested and that a much larger proportion of these were for immediate custody. When the figures for Q4 2011 were initially published, this information was not yet available. However, it would have been possible to track data for Q1, Q2, Q3 and Q4 2010 from their original published values to the version of the figures updated one year subsequently. This information is shown in the table below along with the average change when compared to the figures published a year later for all four quarters.

Table 1: Change between figures initially published for Q1 - Q4 2010 and revised figures published a year later

Sentence type	Q1 2010	Q2 2010	Q3 2010	Q4 2010	Average
Caution	1.6%	0.7%	0.8%	1.4%	1.1%
Absolute/Conditional Discharge	11.4%	9.0%	6.3%	2.6%	7.3%
Fine	3.3%	6.8%	5.2%	8.1%	5.8%
Community Sentence	-0.2%	-1.8%	-3.9%	-1.6%	-1.9%
Suspended Sentence	2.3%	-1.5%	-3.6%	-1.7%	-1.1%
Immediate Custody	17.5%	20.0%	21.6%	15.9%	18.7%
Other Disposal	-48.6%	-47.8%	-44.8%	-42.8%	-46.0%

Clearly the biggest impact seen was an increase in the figures for immediate custody and a related decrease in the ‘other disposal’ category. The table also demonstrates that the direction and scale of change for each of the four quarters was consistent providing confidence that the figures would change similarly for the numbers initially available for Q4 2011.

By applying these average change values for the previous four quarters to the Q4 2011 figures at the time of their initial publication in March 2012, we could have estimated what the final figures for the quarter would be. These estimates are shown below along with the actual revised values as they have been published within this release.

Table 2: Difference between initial figures published for Q4 2011, the revised figures published within this bulletin and the figures that would have been estimated through the method described above

Disposal Type	Q4 2011 (initially published)	Q4 2011 (estimated)	Q4 2011 (revised in later bulletin)	% change - revised vs initial	% change - revised vs estimated
Total	4,781	4,796	4,811	1%	0%
Caution	902	906	914	1%	1%
Absolute/Conditional Discharge	142	150	152	7%	1%
Fine	186	195	194	4%	-1%
Community Sentence	1,420	1,382	1,397	-2%	1%
Suspended Sentence	614	597	586	-5%	-2%
Immediate Custody	1,148	1,368	1,363	19%	0%
Other Disposal	369	198	205	-44%	4%

We continuously assess the accuracy of the estimation method and update the model as more data becomes available. Whilst estimated figures tend to be within a few percentage points of the actual figures, there are often sizeable differences between the non-estimated and the actual final figures for all disposal types, particularly immediate custodial sentences and other disposals. The average accuracy of the estimated figures has been greater than that of the non-estimated figures in every release to date, and as such will continue to be used in future bulletins.

In the Q3 2018 publication a change was made to this methodology and the data from the PNC used to produce these figures was taken one month before the point it was taken previously. As this change reduces the amount of time between the period for which data is being published and the data available on the PNC, we would expect there to be more unknown final outcomes. Cases have had less time to pass through the CJS and are less likely to have final outcomes.

Tables providing a detailed analysis of the accuracy of the estimation method are available on request.

2. Data Quality Statement

2.1 Introduction

Knife and Offensive Weapon Sentencing statistics are published in compliance with the Ministry of Justice quality strategy for statistics, which states that information should be provided as to how the bulletin meets user needs. The MoJ aims to provide a high quality and transparent statistical service covering the whole of the justice system to promote understanding and trust. This statement sets out our policies for producing quality statistical outputs and the information we will provide to maintain our users’ understanding and trust.

We aim to deliver a service in line with our four core objectives:

• Provision of data which are accessible, consistent and fully documented.
• Production of statistics which clearly communicate the story and meet users’ needs.
• Provision of analysis which is timely and based on robust methodology.
• Building capacity, capability and engagement.

Trust in statistics is important as statistics are fundamental to good government, to the delivery of public services and to decision-making in all sectors of society. Statistics provide parliament and the public with a window on society and the economy, and on the work and performance of government. Assessing the quality of statistics is not a one-off exercise. It must be done continuously. This document explains by what measures we will assess the quality of our statistics, what users can expect us to do, and the information we will provide to users to aid them in making their own assessment of the quality of the statistics we produce.

As required by the Code of Practice for Official Statistics and in line with the Government Statistical Service (GSS) Quality Strategy, we will measure and report on our quality using a framework based on European Statistical Systems (ESS) Dimensions of Quality. Statistical quality in the MoJ is defined as meeting users’ needs with particular reference to the relevance, accuracy, timeliness, accessibility, comparability and coherence of the statistics collected, analysed and reported.

2.2 Relevance

Relevance is the degree to which the statistics meet the current and potential needs of users.

The published knife and offensive weapon statistics focus on three different offence types

• Possession of an article with a blade or point in a public place or on school premises
• Possession of an offensive weapon without lawful authority or reasonable excuse in a public place or on school premises.
• Threatening with either type of weapon in a public place or on school premises.

The published statistics help users to understand the volumes of convictions and cautions for these offences in England and Wales, the outcomes offenders receive, whether offenders are convicted or cautioned for other offences alongside these offences, and whether these are first-time knife and offensive weapon offenders. The figures therefore provide a range of information about an aspect of knife crime, currently an issue of public concern.

These statistics strive to be relevant across a range of users, and the statistics production team routinely seeks out feedback from both internal and external users to enhance what is published. To ensure that the statistics remain useful we routinely invite feedback from readers of the publication, as well as using data requests and consulting with policy colleagues to assess any new areas of interest.

We have introduced new statistics when evidence gaps can be reliably filled. For example, figures on other offences offenders are convicted of or cautioned for at the same time as a knife or offensive weapon offence. These figures were initially introduced in response to interest from colleagues wanting to assess whether disposals for these offences are potentially being affected by other offences dealt with at the same time.

2.3 Accuracy and Reliability

Accuracy is the closeness between an estimated result and the (unknown) true value.

Knife and offensive weapon sentencing statistics are calculated using the MoJ copy of the PNC. This is an administrative data system used by police to monitor recordable offences, the offenders convicted or cautioned for them, and the outcomes received by these offenders. The offences covered in the publication are all recordable offences which should be routinely recorded in this dataset.

Despite carrying out validation on entry, prior to submission and within the statistical processes following extraction the data are subject to some inaccuracies inherent in any large-scale data recording system (e.g. mistyped data entries). However, the validation procedures detailed below are felt to be proportionate in reliably minimising the impact that any errors may have on the published estimates.

There are three aspects to the quality assurance checks carried out. These include:

Firstly, checking that data provided by the police is loaded correctly to the MoJ copy of the PNC

• Checking for and correcting any special characters and extra lines which will cause the data to be read incorrectly (e.g. an arrow used instead of an accented s in the name of a foreign court).

• Checking that records of each type (offender, case, offence, disposal etc) have the correct number of variables and making any necessary corrections.

• Checking the correct number of records has been loaded and processed.

• Confirming that variables loaded are in the correct format (e.g. there are no text values when a number is expected for a calculation).

• Checking records rejected for any reason (e.g. a disposal record without any related offence information).

• When, after the load has been run, deleting or merging records which have been deleted or merged on the police copy of the PNC checking that the correct number of records have been deleted or merged.

Secondly, data cleaning and checks are conducted while the data is being extracted and processed.

• Classifying cases where the courtcautionage, the court caution date minus the offender’s date of birth, is less than 10 years as unknown age and excluding them from age breakdowns

• Classifying suspended sentences given to 10- to 17- year olds as community penalties as suspended sentences are not applicable for juveniles

• Correcting for known issues, such as an overcount of cautions for possession of an offensive weapon given by Essex police between Q1 2008 and Q1 2011.

• Checking the consistency of tables. For example, that the quarterly figures add up to the annual totals and that the percentages add up to 100.

• Having a second person check the extraction code and draft tables, filling in a log to confirm they are happy or give comments on issues. Checks will include things like confirming dataset names and conditions have been updated correctly in the code and that calculations are correct.

Finally, sense checking against previous publications and other relevant figures

• Checking there are no big changes in figures for previous periods since the same publication the previous year. If there are large changes, conduct further investigations to find the source of these.

• Checking that the figures make sense compared to other related figures (e.g. Home Office recorded crime figures). While the figures won’t match in this case, any difference in trends should be explainable. For example, a lag in the cases coming through the system or a drop in the proportion of offences resulting in a charge.

Reliability is the closeness of early estimates to subsequent estimated values.

All data is routinely revised for each publication and checks are made to ensure that there are no big changes in figures for previous years from the previous year’s publication.

By the Code of Practice for Office Statistics, the MoJ is required to publish transparent guidance on its policy for revisions.

2.4 Timeliness and Punctuality

Timeliness refers to the time gap between the publication date and the reference period for the statistics.

Each knife and offensive weapon sentencing statistics release is published with a ‘time gap’. This used to be around two months after the end of the reference period. For example, the statistics for the year ending December were published in the following March.

This ‘time gap’ was felt to be timely and allowed us to strike a balance between the need to minimise the delay in releasing statistics and ensuring a robust and high-quality product. It allowed sufficient time for the production and checking of the statistics while making sure people have access to the information as soon as possible.

However, the ‘time gap’ was recently increased after consultation so that, for example, the statistics for the year ending December were published in the following May. This is in line with other sentencing statistics published by the MOJ. Increasing the ‘time gap’ and allowing more cases to conclude before producing the statistics provides more actual values, avoiding the need for estimation and improving the accuracy and coherence of the figures. The estimation methodology was removed from Q4 2020. Background to the historical estimation methodology is provided within Technical Guide Annex 1.

Punctuality is the time lag between the actual and planned dates of publication for statistics.

Knife and offensive weapon sentencing statistics are published at quarterly intervals at 9:30am on a date which has been pre-announced 12 months in advance, in line with the GSS Code of Practice. Any change to the pre-announced release date(s) would follow the approval of the Chief Statistician for the MoJ and we would explain clearly the reasons for the changes to users at the earliest opportunity.

2.5 Accessibility and Clarity

Accessibility is the ease with which users can access the statistics and data.

The knife and offensive weapon sentencing statistics release ensures that a range of statistics regarding knife and offensive weapon offences, detailed above, are published in a single series of Official Statistics releases, available on the gov.uk official statistics calendar.

It comprises a summary report interpreting the figures and the main trends, detailed data tables, an ‘open data’ tool providing statistics on previous knife and offensive weapon offences and a linked interactive Sankey diagram providing a visual representation of outcomes by offence type and previous offences. These are there to address the needs of a range of users. A technical guide published alongside the bulletin is there to aid users’ understanding of the estimation methodology used, technical terms and key events relevant to the offences.

Each release also includes contact details for the lead statistician or respective mailboxes within Data and Evidence as a Service for users to address any concerns. These inboxes are routinely monitored and any queries are actioned as quickly as possible.

Published data tables are available in ODS format as standard, with the ‘open data’ pivot table tool in Excel and accompanying data in a csv file, and the report on the main page in HTML. Where they cannot access the files, users are invited to request the information in an alternative accessible format.

Clarity refers to the quality and sufficiency of the commentary, illustrations, accompanying advice and technical details.

The commentary is written by professional statisticians after discussing the draft figures and main trends, helping users put the figures into meaningful context. All technical terms, acronyms and definitions are explained in the bulletin itself (where appropriate), supporting footnotes in the published data tables and in the supporting guidance documentation. All published data tools are supported by definitional and practical guidance to support users in making accurate and reliable use of the tool functionality.

Each release also includes contact details for the lead statistician, enabling users to provide feedback about things they don’t understand or other things they would find useful.

2.6 Comparability and Coherence

Comparability is the degree to which data can be compared over time, by region or another domain.

Time:

Data is published in the knife and offensive weapon sentencing bulletin for the last 10 years and, where relevant, figures are calculated and available on request going back to Q4 2007. Major breaks in the time series, including the introduction of threatening offences and the introduction of the Criminal Justice and Courts Act 2015, are highlighted in the release. Further details of events relating to these offences can be found in section 1.1.

Where development work is being undertaken on the MoJ copy of the PNC which could or does affect the publication and statistics provided, such as the project undertaken in 2019 to add new variables, this is also brought to the users’ attention.

Region:

It is not possible to directly compare knife and offensive weapon sentencing statistics to those produced by other countries and jurisdictions. Where they have them countries will have different definitions of the offences and use different counting methods, meaning that any comparisons will not be on the same basis. However, the bulletin does provide some statistics by prosecuting police force which allow comparisons to be made between different areas in England and Wales.

Different data sources:

Whilst there are known differences from other datasets which means the figures won’t match, the statistics in the bulletin are sense checked against other similar figures from other sources. These include:

• The Home Office recorded crime figures
• The MoJ criminal justice statistics outcomes by offence data tool.

The recorded crime statistics are higher as they include offences that do not result in a charge. However, the trends are expected to be the same unless there is some explanation. For example, a higher number of cases recorded may not have fed through yet to charges and cases dealt with by the court or the proportion of cases resulting in a charge may have changed.

The sentenced figures in the outcomes by offence data tool are based on court data systems which count each case in the court by main offence, whereas the knife and offensive weapon sentencing statistics figures count all offences whether they are the primary offence or not.

Coherence is the degree to which the statistical processes that generate two or more outputs use the same concepts and harmonised methods.

All outputs in the bulletin are created from the same dataset and use the same data extraction process and variable definitions; although the tables for offences dealt with under the Sentencing Act 2020 use subsets of the data. The main inconsistencies in the outputs are discussed below.

Counts:

Most of the publication is based on offence counts except for Table 6, the pivot table tool and the Sankey diagram. The pivot table tool and Sankey diagram are based on sentencing occasion counts where each sentencing occasion is counted as one even if the offender is convicted of or cautioned for multiple offences. Table 6 includes sentencing occasion counts and offender counts, and the different counting levels are specified.

The reason for using the different counting levels is the different purposes of these aspects of the publication.

• While most of the publication focuses on the number of offences dealt with and the outcomes given, the pivot table tool and Sankey diagram focus on previous convictions or cautions for knife and offensive weapon offences and how that affects the main outcome given. The number of previous convictions or cautions for knife or offensive weapons offences will be the same for each offence on any sentencing occasion and there will only be one main outcome given.
• Table 6 looks at other offences the offender was convicted of or cautioned for on that occasion. The sentencing occasion counts look at how many of the sentencing occasions involve just knife and offensive weapons offences and how many also involve other offence types.

Unknown age/outcome:

This mainly concerns cases where the age category is unknown but also applies to the one case in Q3 2012 where the outcome is unknown. These cases are included in overall totals but excluded from the relevant breakdowns and the fact that the figures won’t add up is footnoted in the relevant tables.

1. Povey & Ors, R. v, Court of Appeal -Criminal Division, May 21, 2008, [2008] EWCA Crim 1261 ↩ ↩²

2. Monterio & Others, R. v, Court of Appeal -Criminal Division, April 16, 2014, [2014] EWCA Crim 74 ↩

3. Police National Computer ↩ ↩²

4. Ministry of Justice ↩