Understanding the complexities of crime statistics

In this blog, our Head Statistics Regulator for Crime and Security discusses the difficulties in understanding and interpreting crime statistics, and what OSR is doing to support producers in improving the quality of crime statistics for England and Wales.

Crime statistics are complex

Statistics on crime are widely used by politicians, governments, researchers, the media, and the public to try to understand the extent and nature of crime. Often, the questions that people want to know the answers to seem relatively straightforward: Is crime going up or down? What types of crime are most common? How reliable are crime statistics? Is it possible to measure all crimes? But answering these seemingly simple questions can be surprisingly difficult.

Understanding and interpreting crime statistics for England and Wales is complex. This is mainly because there are two data sources on crime: statistics from the Crime Survey for England and Wales (CSEW), a household survey of individuals’ experience of crime; and police recorded crime statistics, which capture the number of crimes reported to and recorded by the police. These statistics are published quarterly by the Office for National Statistics (ONS).

Both data sources have their strengths and limitations. The CSEW is the best source for understanding long-term trends in crime covered by the survey. This is because the survey methods have changed little in the last 40 years and the survey is not affected by changes to police crime recording practices or people’s willingness to report crime to the police. In addition, the survey captures crimes that aren’t reported to the police.

On the other hand, the survey doesn’t capture all crimes. For example, as it’s a household survey, it doesn’t capture crimes against businesses and organisations such as shoplifting. There are also challenges with the survey’s response rate, among other factors that affect the quality of the statistics, which led to the temporary suspension of their accreditation.

The police recorded crime statistics are a better indicator of police activity than trends in crime, because many crimes are not reported to the police. However, the statistics do provide insight on some higher-harm but less-common crimes such as homicide or knife crime, which the CSEW does not cover or does not capture well.

The police recorded crime statistics also cover a broader range of offences than the CSEW because the police also record crimes against businesses and organisations and crimes against society and the state, such as drug offences and public order offences. And the police recorded crime statistics are more granular than the CSEW statistics – the number of offences is broken down by police force area.

Due to these strengths and limitations, it’s important to look at both sources together to get the most complete understanding of crime in England and Wales. ONS’s Crime trends in England and Wales article provides a good guide on how to interpret both sources. It explains which source is best for which purpose. For example, it recommends using CSEW statistics to look at trends in fraud but recommends using police recorded crime statistics to look at trends in knife crime.

Our work on crime statistics for England and Wales

Crime statistics are a priority area for our regulatory work. It’s been a particularly busy period for regulatory work on crime statistics, and the coming months will continue to be busy. The quality of the statistics has been our main focus. One of the questions we’ve been focused on is ‘How reliable are the statistics?’.

Today, we published a detailed report on the quality of the police recorded crime statistics for England and Wales. Our review took stock of how data quality has improved since 2014, when we removed the accreditation of the statistics due to quality concerns. We found that police forces have made significant improvements to crime recording in the last ten years. This has given us greater confidence in the quality of the data. But we found some gaps in the Home Office’s oversight of police force data quality and in ONS’s communication of quality that we have asked to be addressed.

One subset of the police recorded crime statistics that we didn’t look at in our review is fraud and computer misuse statistics. That’s because the process for recording these crime types is different from that used for other crime types. We’re aware of the increased public debate about the scale of fraud and its impact on victims. To give this topic the attention it deserves, we’re doing a separate review of the quality and value of fraud and computer misuse statistics. We’ll publish the review later this year.

Like other UK household surveys, the CSEW has suffered from a lower response rate since the pandemic, which has impacted the quality of the statistics. We’re reviewing the quality of the CSEW statistics soon with a view to reaccrediting them.

We recognise that crime will be an important issue in the upcoming UK General Election. To support the appropriate use of crime statistics, we will be publishing a ‘What to watch out for’ explainer at the end of May that provides some tips and advice and sets out some of the common mistakes in public statements about crime that we have seen. It explains that it’s always better to look at the CSEW and police recorded crime statistics together to get an overall picture of crime in England and Wales.

Through this range of work, we are gaining a good understanding of the current state of crime statistics for England and Wales, helping us to support public confidence in the quality and value of the statistics and to continue to promote their appropriate use.

Related Links:

The quality of police recorded crime statistics for England and Wales


A day in the life of a Regulator

In our latest blog, Job, one of our regulators,  demystifies the job of a statistics regulator.

Statistics regulator. It’s quite a strange-sounding job. If you asked a random person on the street what they think a statistics regulator does, they would probably say that it’s someone who regulates statistics. But if you asked them what this means, they would probably draw a blank. Fair enough – most people aren’t familiar with the idea of regulating statistics. 

So, what does a statistics regulator do? A wide range of things! There is no such thing as a typical week – what we do can vary from week to week – but there are some common activities. The journal below gives you a flavour of the kinds of things I do as the lead of a domain in OSR. 


In the morning, I checked our information dashboard, an internal tool developed by our Data and Methods team. It scrapes data from government statistics release calendars, news websites, Twitter, and Hansard, which helps us monitor the release and use of official statistics. I came across several interesting media articles and Twitter threads about hate crime data. I reviewed what they say and decided that there’s nothing I need to investigate further. 

In the afternoon, I spoke to a couple of users – an academic and a think tank – of Home Office’s police officer uplift statistics, which report on progress with the recruitment of an additional 20,000 police officers in England and Wales. We recently assessed these statistics against our Code of Practice for Statistics (the Code). Assessment is one the main tools we use to review whether statistics are meeting the standards of trustworthiness, quality and value set out in the Code. Speaking to users is a really important part of assessments. It helps us understand what the statistics are used for and what users think of their trustworthiness, quality and value, to identify where improvements can be made. 


In the morning our Head of Private Office and Casework Manager emailed me about a piece of casework I’ve been working on. Casework is what we call our work investigating issues raised with OSR. We have an interventions policy that sets out when and how we intervene in the use of statistics. We can raise casework ourselves internally or members of the of the public can raise casework with us, which could be anything from something which was identified as misleading in a government report, to something a Member of Parliament (MP) said on Twitter. For the case I worked on today, I investigated the concerns raised, prepared a briefing with a summary of the issues, analysis of the statements and statistics, and recommendations for what we should do next.  


My morning started with two back-to-back team meetings: a site catch-up and an organisation-wide “Cascade” with colleagues in the Edinburgh, London and Newport sites (and those based elsewhere). It’s a chance to hear about what’s happening across OSR and to share any important updates. In today’s meeting I gave an update about the domain I work in, alongside the seven other domains in OSR. We also heard about next year’s business planning from our Senior Leadership Team.  

Every other Wednesday afternoon we have team learning sessions. These are mostly used to share knowledge across the team, but we also use them to discuss ways of improving how we work. Today is a ‘Code Case Learning’ session, where two colleagues presented some regulatory work that they’ve been involved in covering a specific principle of the Code of Practice for Statistics. The idea is to help regulators develop their understanding of aspects of the Code and hone their judgement in applying the Code.      


In the morning I met with the Deputy Head of Profession for Statistics and Head of Publications at the Ministry of Defence (MOD). We discussed new developments to their statistics and an idea I have for a short review of a set of MOD statistics. As regulators, we meet regularly with statisticians in different departments to find out what is happening with their statistics and how we can best support them to meet the standards of the Code. 

I spent the afternoon drafting a letter to the Department of Justice in Northern Ireland setting out the results of our compliance check of their prosecution and conviction statistics. Compliance checks are another tool we use to review statistics against the Code. They’re shorter and less detailed than assessments, which allows us to review a wide range of statistics every year.       


Friday is my non-working day. OSR and the Civil Service offer flexible working arrangements, which is great for maintaining a work-life balance. 

On Fridays, our Director General, Ed Humpherson, sends a weekly update to the whole team reflecting on the activities and events of the week. It’s great to hear about Ed’s external meetings and the impact of our work is having. It’s a good reminder of the difference that regulators can make!  


What we’ve learned from the Defra Group about user engagement

Note: this blog post was updated on 27 August 2020.

Today we published the findings of our review of user engagement in the statistics producers that make up the Defra Group. The Defra Group produces a large and broad collection of statistics covering many topic areas, including food, farming and the environment, and the statistics have a wide range of users and uses.

When we review compliance with the Code of Practice for Statistics, we often look at how individual teams engage with their users. With this review we have looked much wider. This approach, the first time we’ve looked at user engagement in this way, has allowed us to understand how individual teams and the Defra Group as a whole engage with their users and to identify the key factors that can make user engagement effective and impactful. We focused our review on a set of 10 statistics which reflects the diversity of Defra Group statistics.

Although the target audience for the report is the Defra Group, we hope that other statistics producers will find it helpful, including our framework of Telling users about the statistics, Understanding use and Listening to users, and use it to inform their thinking about user engagement. We will be adding case studies from the report to the online Code of Practice as examples of best practice in user engagement.

The world has changed dramatically in recent months due to COVID-19. This means that statistics teams may have to become more creative in engaging with users and move more discussions with users online. We recognise the challenges of COVID-19 for the Defra Group and have recommended that teams take a flexible and proportionate approach to user engagement.

We’re not the only ones with an interest in user engagement. The Government Statistical Service (GSS) Best Practice and Impact Division is currently developing a new strategy for user engagement which will be published later this year. Have a look at Tegwen Green’s blog, also published today, which gives an update on this important work. Our review of Defra Group user engagement complements the work on the new GSS strategy, and we will continue to work closely with the Best Practice and Impact team to support its development.