The methodology adopted for assaults, MDTs and purposeful activity allocated a red indicator if the prison in our study scored in the worst performing quartile for prisons of a similar category such as male local prisons, Category B prisons, YOIs and juvenile centres. This allowed for variances associated with different categories of prisons; for example, assaults are generally higher in juvenile centres than in adult prisons. As an example, the upper quartile for male local prisons for purposeful activity (pa) was 17.6 hours per week (h/w). Hence Manchester, with an average pa of 19.7 h/w, did not score a red indicator, whereas High Down, which has an average pa of 15.9 h/w, did score a red indicator.