AI RESEARCH
The Likelihood Ratio Wall: Structural Limits on Accurate Risk Assessment for Rare Violence
arXiv CS.LG
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ArXi:2604.27282v1 Announce Type: cross Pretrial risk assessment tools are used on over one million U. S. defendants each year, yet their use for predicting rare violent re-offense faces a basic statistical barrier. We derive a universal precision bound -- the Likelihood Ratio Wall -- showing that when violent re-arrest rates are low (2-5%), achieving even a 50% hit rate among people labeled "high risk" (positive predictive value, or PPV) would require tools far discriminative than current instruments appear to be.