----------------------------------------------------------------------+Appendix table 2. Estimating the prevalence of imprisonment in theU.S. population for persons born in 1980+Population of 100,000 births, 1980, reduced by mortality andincarceration in each successive year of ageNumber aliveand not Rate of first Survivingincarcerated admission to Expected cumulativeat beginning Number Expected State or number of number ofAge at of age dying per number of Federal prison first first Prevalencefirst interval 100,000 deaths[a] per 100,000 admissions[b] admissions[c] percent[d]admission Year (1) (2) (3) (4) (5) (6) (7)0-13 1980-93 100,000 ... 1,732 0 0 0 0.000%14 1994 98,268 44 43 1 1 1 0.00115 1995 98,224 57 56 5 5 6 0.00616 1996 98,163 73 72 39 38 44 0.04517 1997 98,053 84 83 135 132 176 0.18018 1998 97,838 93 91 283 277 453 0.46219 1999 97,470 93 91 346 337 789 0.80620 2000 97,043 94 91 355 344 1132 1.15821 2001 96,607 96 92 356 343 1474 1.510Note: Calculations for ages 0 to 13 were based on data for eachsingle year of age and then grouped for presentation.... Not shown, because calculations were based on rates for singleyears of age.[a] To estimate the number expected to die at each year of age,age-specific mortality rates(column 2) were multiplied by the numberof persons alive and not previously incarcerated (column 1).[b] To estimate the number expected to go to prison at each year ofage, age-specific first admission rates (column 4) were multipliedby the number of persons surviving (column 1 minus column 3).[c] To estimate the surviving number of first admissions, the numberof first admissions from the x-th year of age (column 5) were addedto the number of surviving first admissions from the x-1 year of age.Mortality rates for ex-prisoners by age were based on mortality ratesin the general population and adjusted to reflect higher ex-prisonermortality.[d]To estimate the prevalence percent, this procedure was followed.The surviving number of persons ever incarcerated (column 6) wasdivided by the total number of surviving persons never incarcerated(column 1 minus both columns 3 and 5) and persons ever incarcerated(column 6), times 100%.----------------------------------------------------------------------
----------------------------------------------------------------------Appendix table 3. Estimating the prevalence of imprisonment in theU.S. population for persons born in 1970Population of 100,000 births, 1970, reduced by mortality andincarceration in each successive year of ageNumber alive Rate of firstand not admission Survivingincarcerated to State Expected cumulativeat beginning Number Expected or Federal number of number ofof age dying per number of prison per first first PrevalenceAge at first interval 100,000 deaths[a] 100,000 admissions[b] admissions[c] percent[d]admission Year (1) (2) (3) (4) (5) (6) (7)0-13 1970-83 100,000 ... 2,099 0 0 0 0.000%14 1984 97,901 49 48 1 1 1 0.00115 1985 97,852 62 61 0 0 1 0.00116 1986 97,791 73 71 24 23 24 0.02517 1987 97,697 86 84 74 73 97 0.09918 1988 97,539 96 94 186 181 278 0.28519 1989 97,265 102 99 265 258 535 0.54920 1990 96,907 107 103 331 320 855 0.87821 1991 96,484 110 107 266 257 1,110 1.14222 1992 96,121 113 109 305 293 1,402 1.44423 1993 95,719 111 106 272 260 1,660 1.71124 1994 95,353 108 103 279 266 1,924 1.98525 1995 94,984 104 99 230 218 2,139 2.21026 1996 94,668 100 94 232 219 2,356 2.43627 1997 94,354 100 94 217 205 2,558 2.64828 1998 94,055 97 92 257 241 2,796 2.89729 1999 93,722 102 95 218 204 2,997 3.10830 2000 93,422 104 97 275 257 3,250 3.37431 2001 93,068 110 102 218 203 3,448 3.584Note: Calculations for ages 0 to 13 were based on data for eachsingle year of age and then grouped for presentation.... Not shown, because calculations were based on rates forsingle years of age.[a] To estimate the number expected to die at each year of age,age-specific mortality rates(column 2) were multiplied by the numberof persons alive and not previously incarcerated (column 1).[b] To estimate the number expected to go to prison at each year ofage, age-specific first admission rates (column 4) were multipliedby the number of persons surviving (column 1 minus column 3).[c] To estimate the surviving number of first admissions, the numberof first admissions from the x-th year of age (column 5) were addedto the number of surviving first admissions from the x-1 year of age.Mortality rates for ex-prisoners by age were based on mortality ratesin the general population and adjusted to reflect higher ex-prisonermortality.[d] To estimate the prevalence percent, this procedure was followed.The surviving number of persons ever incarcerated (column 6) wasdivided by the total number of surviving persons never incarcerated(column 1 minus both columns 3 and 5) and persons ever incarcerated(column 6), times 100%.----------------------------------------------------------------------
Limitations
1. The data in this report are restricted to incarcerations in State or Federal prison. Excluded are prior incarcerations in local jails and juvenile facilities because of the lack of data needed to estimate the number of first admissions to these forms of correctional supervision.
2. Estimates of the number of first admissions are subject to sampling and nonsampling errors. Because the numbers of first admissions are based on a sample rather than a complete enumeration, the estimated number of first admissions may vary depending on the size of the estimate and the base population for each demographic group.
Nonsampling error can be attributed to many sources, such as nonresponse, differences in interpretation of questions, recall difficulties, and processing errors. Among inmates, the number of first admissions may be slightly overestimated because of underreporting of criminal histories. The full extent of nonsampling error is unknown.
3. No comparable inmate survey was conducted prior 1974 to enable the calculation of first incarceration rates prior to this date. First incarceration rates in 1970 and earlier were estimated to be 80% of each age-specific rate of first incarceration in 1974.
If first incarceration rates in 1970 and earlier had averaged 90% of each age-specific first incarceration rate in 1974, the estimated number of adults alive in 2001 who had ever gone to prison would have been 1.9% higher (5,723,000). Alternatively, if earlier first incarceration rates had averaged 70% of 1974 rates, the estimated number of persons ever to have been incarcerated in 2001 would have been-1.9% lower (5,513,000).
4. Mortality rate schedules for prisoners were not available. Compared with the general population, mortality rates for prisoners were estimated to be 20% higher for adults under age 65, and the same for those age 65 and older. The estimate was based on the lower overall educational attainment of prisoners, and longitudinal studies documenting the relationship between mortality and educational attainment.
If mortality rates for adults ever incarcerated, under age 65 were instead 40% higher than that of the general population, the estimated prevalence of ever having gone to prison in 2001 would be 5,567,000 (-0.9% less). If mortality rates for prisoners had been equal to that of the general population, the estimated prevalence would have been 0.9% higher in 2001 (5,670,000).
5. Comparable mortality rates prior to 1976 were not available. However, there is minimal effect of declining mortality rates since 1900 on the estimated number of persons ever incarcerated. Prevalence rates are only affected to the extent that there may have been a different decline in mortality among those ever incarcerated (the numerator) compared with all surviving members of a birth cohort (the denominator). Furthermore, prevalence rates were applied to estimates of the U.S. resident population (which fully reflect declines in mortality).
6. Age-specific incarceration rates do not incorporate a forecast of future rates of imprisonment, which may be affected by changes in criminal behavior, law enforcement, and in sentencing policies. Consequently, the lifetime likelihood of incarceration, 2001, and projected prevalence rates for 2002 and beyond may be different.
A fuller description of the methodological techniques used in preparing this report is available upon request from the author.
The Bureau of Justice Statistics is the statistical agency of the U.S. Department of Justice. Lawrence A. Greenfeld is director. BJS Special Reports address a specific topic in depth from one or many data sets that cover many topics.
Thomas P. Bonczar wrote this report, under the supervision of Allen J. Beck. Tom Hester and Carolyn C. Williams edited the report. Jayne E. Robinson administered final production.
August 2003, NCJ 197976
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