To the Editor: Draine and Muñoz-Laboy’s (1) commentary on my review (2) in the July issue raises a point that is crucial (although they misattribute a motivating logic to my analysis): targeting an individual risk factor for incarceration, such as mental illness, will likely not reduce incarceration rates. This is because the causes of individual “cases” of incarceration are almost certainly not the same as the causes of changes in incidence rates of incarceration (3). This is true of any individual-level intervention for a population (social) phenomenon. Furthermore, research has shown that incarceration rates for people with mental illness have remained relatively stable (4). So why obtain better prevalence estimates of mental illness in prisons?