Abstract: Many criminal justice reformers see risk-based sentencing—where an offender’s likelihood of returning to crime determines the amount of time they spend in prison—as a fair and efficient way to shrink the size of the incarcerated population, while minimizing sacrifices to public safety. But, as this article shows, risk-based sentencing is indefensible—even assuming the truth of a number of controversial premises that proponents take to be sufficient for its justification. Instead of trying to cut sentences for those who are least likely to reoffend, officials should focus sentence reductions on the least well-off—who tend to be the most likely to reoffend.