Ethnicity and custodial sentencing data highlights racial bias

In June 2021, the Sentencing Academy published Ethnicity and Custodial Sentencing: A review of the trends, 2009-2019 (‘The Report’). As the name suggests, the Report considers comparative sentencing trends across different ethnic groups between 2009 and 2019 (‘The Relevant Period’), applying a variety of methodologies. At the outset, we note that the Report only examines custodial sentencing patterns for adults; however, its findings offer useful insight which can be applied to children and young people.


The Report is grounded in its opening question: are sentencing outcomes different for ethnic minority defendants as compared to White defendants? Perhaps unsurprisingly, the answer is, yes.

The Report opens on a note of caution arising from certain methodological issues. Purely ethnocentric summary data does not take into account certain other legally-relevant characteristics, including: criminal histories; guilty pleas; and demonstration of remorse. That summary data also encounters issues in how ethnicity is classified, whether by self-identification, officer-identification or otherwise. The summary data presented in the Report indicates, but is not conclusive of, bias.

Pure custodial data

Over the Relevant Period the ‘Chinese & other’ category experienced the highest custody rate for indictable offences of 39%, followed by Black and Asian (both 34%), Mixed (32%), and White at 29%. However, over that period the gap between White and minority groups has narrowed. In 2019, the figures were: Chinese & other 37%; Black, Asian and Mixed each 36%; and, White 34%.

Average custodial sentencing lengths (‘ACSL’) over the Relevant Period reveals a different pattern: Black 24.6 months; Asian 24.Perhaps more pertinently, the gap in ACSLs has widened over the Relevant Period.

Given the divergent patterns, the Report suggests that a more accurate means of highlighting ethnocentric sentencing disparities is by combining custody rate data with ACSL data to arrive at the “Expected Custodial Sentence” (‘ECS’). This is achieved by multiplying the custody rate by the ACSL: for example, in 2019 the Asian custody rate was 36% and the Asian ACSL was 28.2, thereby producing and ECS of 7.95. Over the Relevant Period, ECS data showed (again in descending order): Black 9.2; Asian 8.4; Chinese & other 7.6; Mixed 6.5; and White 5.0. However, over the Relevant Period the ‘imprisonment gap’ between White and minority categories has lessened. The problem with ECS data is that it does not take into consideration variation across offence categories. For example, for “violent offence against the person” the data shows: Black 20; Chinese & other 16.1; Asian 14.7; Mixed 14; and, White 7.4, whereas there is a greater degree of parity in other offence categories.

Other data sources

As noted above, research has shown that a deeper matrix of data (beyond pure custodial data) is required in order to develop a proper understanding of custodial divergence between ethnic groups. In particular, the Report highlights the following:

  • Based on information from the Police National Computer in 2011, the chances of those from a BAME background being sentenced to prison increased by 39% as compared to White offenders.
  • Black and Asian offenders are less likely to enter a guilty plea, with the effect of increasing ACSLs for those ethnic groups.
  • Black males are 20% less likely to be sentenced to custody in the Magistrates’ Courts, as compared to White males; however, the situation is 12% in the reverse out of the Crown Court (for women the difference is 25%). However, it should be noted that there is a paucity of available data from the Magistrates’ Court.
  • The odds of BAME offenders receiving custodial sentences for drugs offences are more than double that of White offenders. Research applied by the Report underlines that this disproportionality is traced back to a combination of disproportionate arrest rates and custodial sentencing.
  • Analysis from 2019 showed that BAME adults accounted for just over 40% of stop and search incidents.


The Report leaves two fundamental conclusions: (i) White adults are, across the board, less likely to be imprisoned than non-White adults; and (ii) despite the wide variety of statistical data available, it does not explain the first conclusion. The natural conclusion is that (something which the last year should have finally squeezed into daily consciousness) racial injustice is so deeply rooted in society that it requires far more than statistical data in order to understand its cause.

As the Report states, understanding the magnitude of the differentials between ethnic sentencing is a vital first step, but the real question for society to confront is: why? Why are BAME adults accounting for 40% of stop and search incidents, when White adults account for 87% of the population? Why are Black adults more likely to enter a plea of not guilty? Why is there such a differential between White and Non-White when it comes to drugs-related offences? Why do BAME adults have less confidence in the criminal justice system?

The unsatisfactory answer to those questions, as the Report ultimately concludes, is that we do not have a complete understanding of the problem. Whilst the data does demonstrate a narrowing of ethnic divergence in sentencing (for the most part), the simple fact remains that you are more likely to be treated harshly by criminal justice if you are not white.

Whilst the data focuses only on adults, our experience suggests that similar disparities exist for children and young people in the criminal justice system. Further scrutiny of the data, and a focus on rigorous data collection would assist in identifying the factors affecting this disproportionality and thereby help to inform policy. This is particularly important as the first experience, or early experiences, of the criminal justice system can be crucial interventions impacting the fact or frequency of reoffending. If children and young people from non-White ethnic backgrounds are also treated more harshly by the criminal justice system it is likely to compound the problem and increase the disproportionate representation of ethnic minorities in the prison population.


Written by
Jonathan Robb, 
Associate, Paul Hastings