Data

This section contains links to the source data that supports policing information shown on this website. Please choose a dataset from the menu to the left. The data available on this site is licensed for use under the Open Government Licence. HMICFRS is committed to making the data it collects easily accessible. If you have any queries regarding the content of this section, please email contacthmicfrs@hmicfrs.gov.uk.

Identifying differences between forces’ data

We identify differences between all forces based on their data. Our inspection staff use this insight to guide their main lines of enquiry to forces. We highlight that a force is higher than, lower than or within the typical range when compared to all forces in England and Wales for which data is available. We don’t conclude that the comparisons are statistically significant. And if a force is lower or higher than the typical range, this doesn’t have a direct impact on its graded judgment. All data is triangulated with other inspection evidence, and we judge forces against our characteristics of good for the relevant inspection.

Methodology

We consider a force to be higher or lower than the typical range if it is at least twice as far from the median as the first or third quartile of the data. We previously considered a force to be a potential outlier – that is, when the data could be meaningfully different – if it was more than one standard deviation above or below the mean. When we reviewed our inspection framework for our 2025–27 PEEL inspections, we changed our methodology because:

• extreme values have a smaller impact on the median than on the mean, which means that the median is a more robust estimate of the centre of the data; and
• by using quartiles, we don’t assume the data is symmetrically distributed, and this allows us to better reflect the nature of our data and identify values that are higher or lower than the typical range for forces.

Data comparators

HMICFRS most often uses England and Wales (sometimes referred to as national) averages or Most Similar Groups (MSGs) to provide comparators for policing data. MSGs are groups of police force areas that have been found to be the most similar to each other based on an analysis of demographic, social and economic characteristics which relate to crime. With the exception of the City of London Police (for which it was not possible to identify any most similar forces), each force area has its own group of up to seven force areas to which it is ‘most similar’. They are designed to help make a fairer comparison between police forces than the England and Wales average can sometimes offer. Although caution should still be used in making black and white comparisons between forces, even in the same MSG. For more information about MSGs and how they are formed, please see the MSG technical note (PDF document).

MSGs by force