The impact of incarceration is to simply drive productivity for such an individual even lower - that is, to zero. Thus, while the incremental productivity-related cost of incarcerating such a person is only a portion of the potential productivity for a member of the general population, to this must be added the cost representing the productivity decrement such a person experiences even when available for the labor market. This distinction is critical because the incarceration cost component does not estimate the added productivity-related cost of incarceration so much as it estimates the loss of productivity associated with those individuals who are incarcerated. Those individuals have a total loss of potential expected productivity because their current and past alcohol and drug problems reduce their expected productivity when they are available for the labor market, and even this lower productivity is lost due to incarceration. This logic is strengthened by analyses that find that a major impact of early initiation of drinking and drug use can be to reduce educational attainment.
Poor education limits success in the labor market.
Most studies of offender populations have found both early onset of drinking and drug use and high dropout rates. It is plausible that these may be causally linked. The value of reduced productivity for those incarcerated in prisons has again been calculated using the methodology developed by Cruze et al. The detailed calculations appear in appendix B . There were 1.3 million person-years spent in prisons and jails in 1992.