Safer Outside than Inside? The Prison Homicide Paradox and the Problem of Reported Zero
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Abstract
Deaths caused by intentional violence are a particularly serious test of safety in prisons, yet comparative prison-homicide statistics remain uneven. Using two United Nations Office on Drugs and Crime workbooks, the study compared recorded prison homicide with national homicide rates from 2018 to 2023. It distinguished explicit zero counts from missing reports and calculated custodial homicide rates using prisoner stocks rather than national populations. The files contained 370 reported prison-homicide country-years, including 229 explicit zeros. Of these, 347 country-years from 72 countries and territories could be paired with the required denominators. In the main sample of 63 areas with at least three matched years, 24 had a pooled prison-to-national homicide rate ratio above one, while 31 had no recorded prison homicides in their matched years. Among 34 areas with all six years available, 19 had a ratio above one. An exploratory comparison of 57 areas found a weak association between prison occupancy and custodial homicide rates, with Spearman rho of 0.164 and a two-sided p value of 0.221. The estimates varied substantially with reporting coverage. The findings indicated that cross-national comparisons required explicit reporting of zero cases, missing observations and population denominators.
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