Young people self-report their ethnicity. Staff working in secure training centres and young offender institutions then record this information on an administrative system.
The numbers of young people in custody are counted at the beginning of each month, updated to include new admissions during the month, and then averaged across a 12-month period.
Percentages have been rounded to 1 decimal point. Due to this, some figures may not add up to 100. Counts have been rounded to the nearest whole number. All calculations have been made using unrounded figures.
See the Youth justice annual statistics for unrounded figures and the percentages calculated from them.Quality and methodology information