Missing data and disproportionality

Missing data and disproportionality

In her recent audit on group-based child sexual exploitation and abuse, Baroness Casey found that she could not make any statements about the ethnicity of perpetrators or victims at the national level because the ethnicity recorded is so poor.

The Casey audit team had to draw on data they obtained from three local police forces, previous reviews and case studies to make conclusions about the ethnicity of perpetrators in particular. They could not make any nation-wide claims because ethnicity was not recorded for about two thirds of the suspects in the national data.

Casey was looking at one very specific kind of crime but the poor collection of ethnicity data is a far more general issue in criminal justice. In a report we published this week on young adults (18-24) in the criminal justice system, we note that — according to Ministry of Justice statistics — 37 per cent of young adults prosecuted for non-summary offences in 2024 were recorded as having an ‘unknown’ ethnicity. This does not appear to have always been the case. The same statistics show that ‘unknown’ ethnicity only accounted for seven percent of young adults prosecuted in 2010.

As Casey argues, unrecorded or unknown ethnicity data makes it hard to assess disproportionality. In our case, it has made it difficult to ascertain the trend in disproportionality because we can be much more confident in claims about disproportionality in 2010 than what we can about 2024.

For example, in 2010, Black young adults made up eight percent of prosecuted young adults for non-summary offence and nine per cent of those sent to prison. Meanwhile, the 2011 census showed that Black young adults only made up about four per cent of the general population of young adults.

By 2024, Black young adults made up seven per cent of prosecuted young adults (but 11 per cent of those with known ethnicity) and nine per cent of those sent to prison (but 13 per cent of those with known ethnicity) when the 2021 census showed they only made up about five per cent of the general population of young adults.

In both 2010 and 2024, Black young adults were over-represented in prosecutions for non-summary offences and even more over-represented among those then sent to prison. Given the increasing percentage of Black young adults among those with known ethnicities, is it possible that the disproportionality has also grown? Without 37 per cent of the ethnicity data, it is hard to tell for sure.

Missing data is a problem, but it really exacerbates the challenges of interpreting small groups of data within large aggregate sets. In our report, we tried to draw out trends by gender and ethnicity, but analysing the intersection of both proved difficult. Young women from minoritised groups (Black, Asian, Mixed and Other in the official statistics) make up a tiny percentage of young people in the criminal justice system. When groups are small in number they can get easily lost in the aggregate data and it is hard to draw out trends and averages that really tell us something specific about them.

The Corston Report noted in 2007 that women are a minority within the criminal justice system but, within that group, Black and minority ethnic women are an even smaller minority. They are more likely to be remanded than White women and continue to be disadvantaged throughout the system and in resettlement services.

We also know that women from minoritised groups can have traumatic encounters with the criminal justice system that are specific to both their gender and ethnicity. StopWatch, for example, published a report this year on young women and girls’ experiences of stop and search. One thing that emerges from the harrowing stories their research participants shared is that, for many of those interviewed, these experiences “were compounded by existing at the intersection of being simultaneously gendered and racialised.” The depth and sensitivity of this kind of qualitative research not only explains how interactions with the criminal justice system actually impact women's lives. It provides a platform for perspectives that are not usually heard.

These accounts make it all the more clear why it is so important that official statistics should also capture the experiences of minoritised young women, whose specific challenges are not often addressed. If young women are marginalised within the columns of a spread-sheet, we should hardly be surprised if their needs are not being properly addressed.

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