The PLRA ended free access to Federal district court for all inmates and effectively ended access altogether for many indigent repeat litigants. The study hypothesized that incarcerated population levels would vary positively with inmate filings and that the relationship would be somewhat different for jail and State prison populations. Further, the study expected that the PLRA would have the effect of dampening the relationship between prison population and filings and that the effect on the jail population-filings relationship would be less clear. The test of these hypotheses used three econometric models. Each model used a panel of inmate filings in Federal court by State and year, so that coefficients were identified by changes in the explanatory variables within a State rather than the cross-sectional differences across States. In addition to the controls for State and time, the models also included inmate populations and interactions between inmate populations and legal regime. The differences among the models involved how the dependent variable and the error term were specified. Despite the different approaches, overall the models were broadly consistent with each other, and all at least partially supported the hypotheses. The PLRA was found to have a larger dampening effect for prison inmates than for jail inmates, which was on the order of 25 percent. Even since the PLRA's enactment, State prison inmates have tended to file more cases than jail inmates, although the extra increment in litigation was smaller than it was prior to 1996. The variables that contribute to this difference in filing rates between jail and prison inmates is the lower level of order and amenity in jails, facility size, criminal status, and population flow. 3 tables and 1 figure