Frequently Asked Questions
What is the difference between jails and prisons?
Jails are locally operated short-term facilities that hold inmates awaiting trial, awaiting sentencing, or both, and those sentenced to a term of less than or equal to 1 year, typically misdemeanants. Prisons are longer-term facilities run by the state or federal government typically holding felons and persons with sentences of more than 1 year. Definitions may vary by state.
What is the difference between custody and jurisdiction counts?
Between 1926 and 1976, the official measure of the prison population was the number of inmates in the custody of state or federal correctional officials. State and federal reporting officials were instructed to count all prisoners physically housed under their authority, regardless of whether they or some other entity had legal authority over the inmates.
As states and the Federal Bureau of Prisons increased their use of local jails and interstate compacts to house inmates, NPS began asking states to report a count of inmates under the jurisdiction or legal authority of state and federal adult correctional officials in addition to their custody counts.
Since 1977, the jurisdiction count has been the preferred measure of the prison population. This count includes all state and federal inmates held in the physical custody of public or private prisons, inmates held in jail facilities located either inside or outside of the state of legal responsibility, and other inmates who may be temporarily out to court or in transit from the jurisdiction of legal authority to the custody of a confinement facility outside that jurisdiction.
What does "sentenced prisoner" mean?
Prisoners can be sentenced to varying lengths of time. To standardize across states and to capture felons instead of misdemeanants, BJS uses the term "sentenced" to indicate individuals who have received prison sentences of more than 1 year. This often corresponds to state policies on which inmates are housed in prisons versus in jails (jails hold inmates with sentences of 1 year or less) but not for all states.
Why can't I create custom tables by race?
BJS plans to offer the racial distributions for some variables in the future. The race data collected in the National Prisoner Statistics program come from administrative data used in the operation of prisons and don't always reflect how an inmate would identify himself or herself by race and ethnicity. When BJS publishes racial distributions, the data are weighted to reflect more accurately the distribution of race and ethnicity collected from inmates in our face-to-face surveys.
Why can't I create tables showing data before 1978?
In 1977, BJS changed from publishing the number of inmates in the physical custody of state and federal prison facilities to those under the jurisdiction (legal authority over inmates) of the states and the Federal Bureau of Prisons. All states began reporting jurisdiction counts in 1978. While custody and jurisdiction counts tend to be close to one another, they are not the same.
Where can I download these data to use on my own?
The full National Prisoner Statistics (NPS) data set is archived at the National Archive of Criminal Justice Data website at https://www.icpsr.umich.edu/web/NACJD/series/886.
Are there any data for prison populations prior to 1978?
The National Prisoner Statistics (NPS) program has collected aggregate data on state and federal prison populations since 1925. Total prison and resident population data for 1925 to 1977 can be downloaded for analysis at the National Archive of Criminal Justice Data (https://www.icpsr.umich.edu/web/NACJD/studies/8912/versions/V1). Unfortunately, that file does not break down the prison population down by sex or race. There have been several reports published on the historical data that do show breakdowns by sex and race:
- Prisoners 1925-81
- State and Federal Prisoners, 1925-85
- Race of Prisoners Admitted to State and Federal Institutions, 1926-86.
How do I calculate an imprisonment rate?
Imprisonment rates are calculated by dividing the counts of prisoners in a particular year by the U.S. resident population for that year, then multiplying by 100,000. Imprisonment rates are reported per 100,000 U.S. residents for that year.
How do I find out about the number of people in private prisons?
BJS began publishing statistics on private prisons in 1999. To find the count or rate of inmates in private prisons, go to the Custom Tables tab, select the jurisdiction and year or years for which you would like to know the number of persons in private prisons. Select "Year-end population" from the Population menu, and then select one of three options from the First Variable menu: Jurisdiction population - total held in private prisons; Jurisdiction population - held in in-state private prisons; Jurisdiction population - held in out-of-state private prisons.
How many prisons are in my state?
The best way to find out about prison facilities in a particular state or jurisdiction is to find the website for the state’s department of corrections. All states have these, and many allow you to link to information on particular facilities.
How can I tell if prisons are overcrowded?
We have a quick table on the prison capacity numbers reported to BJS by each state and the Federal Bureau of Prisons, and facility custody counts. We then show what percentage of the capacity was in use on December 31 of a particular year.
When are more recent data going to be available?
The reference day for NPS is December 31 of a given year. This means that we can't start collecting data for the reference year until the first day of the next year. We ask states to submit their data by February 28, but not all states can meet this goal.