In sentencing research, significant negative coefficients on age research have been interpreted as evidence that actors in the criminal justice system discriminate against younger people. This interpretation is incomplete. Criminal sentencing laws generally specify punishment in terms of the number of past events in a defendant's criminal history. Doing so inadvertently makes age a meaningful variable because older people have had more time to accumulate criminal history events. Therefore, two people of different ages with the same criminal history are not in fact equal. This is true for pure retributivists, as the fact that the younger offender has been committing crimes at a higher rate of offending may make the younger offender more culpable, and is also true for those with some utilitarian aims for sentencing. Simulation results illustrate the stakes. To a certain extent, the interests of low-rate older offenders are opposed to those of high-rate younger offenders. (Contains 10 notes, 6 tables and 4 figures.)