Years Lost Inside and Outside of Prison by Sex
details the years of life lost by sex and race of people incarcerated in U.S. state correctional facilities and the U.S. civilian population for the selected states. The first column lists the demographic group studied. The top row displays the period, with subheadings underneath indicating the population estimated (imprisoned or not imprisoned). The next row provides the number of years lost for persons in prison, followed by persons in the U.S. civilian population and the ratio of years lost by prisoners to years lost by the nonprison population. Asterisks by the ratio denote that it is significantly different from 1, indicating that mortality differs significantly between the two populations.
Expected Number of Years Lost Between Ages 18 and 65, by Sex and Race: U.S. State Correctional Facilities Versus the U.S. Population, Selected Statesa
During the first period, 1985–1987, male prisoners lost 13% more years of life than male nonprisoners, and female prisoners lost 76% more years of life than female non-prisoners. Over time, the ratio decreased for both female and male prisoners. Calculated confidence intervals for the ratios (not displayed) confirm that the male/female ratios and the prisoner/nonprisoner ratios changed across periods. Despite the significant decrease across the three periods, female prisoners still fared worse than female nonprisoners in the last period. In contrast, by the last period, male prisoners actually fared slightly better than male nonprisoners.
Another feature of is the ratio of the years of life by sex, computed separately for prisoners and nonprisoners. In the first period, the male-female ratio of years lost in the civilian population was 2.04. That is, males lost twice as many years of life as females between the ages of 18 and 65. However, inside prison, that ratio was 1.31. Furthermore, the ratio between males and females in prison increased significantly between the first and second periods; nevertheless, the ratio between males and females in prison was always less than the ratio between males and females outside of prison.
The bottom section of displays the differences in years of life lost between the ages of 18 and 65 for males by race. The racial comparison focuses on white and black males because these two groups make up the majority of prisoners (94%–96%), thus providing enough cases to produce stable estimates.6
Ideally, data on ethnicity would permit further partitioning of males. Unfortunately, there were year-to-year inconsistencies for the ethnicity variable. Rather than classifying them as a separate ethnic group, I included Hispanics based on the racial category (either black or white) denoted in the NCRP and inmate surveys.
Within these limitations, the data analyses revealed four significant findings: (1) Black male prisoners exhibited lower death rates than their nonprison counterparts; (2) By the last study period, black male prisoners, white male prisoners, and white male nonprisoners exhibited no significant difference in their age-specific mortality rates; (3) Safety alone did not explain the lower mortality of black males; and (4) Prisoners experienced lower mortality than their socioeconomic status implied. I discuss these findings in detail below.
Years Lost Inside and Outside of Prison by Race
Between 1985 and 1987, white males in prison lost 32% more years of life than white males not in prison, but black males in the nonprison U.S. population lost more years of life than those inside prison. The ratio for white males in and outside of prison approached 1 over time, although the ratio was always statistically significantly different from 1. In contrast, the relative gap between years of life lost for black males in and outside of prison widened between the first and last periods. In the last period, black males not in prison lost almost twice as many years of life between the ages of 18 and 65 as black males in prison. White males lost slightly more years of life in prison than outside of prison (2.850 vs. 2.597), with a ratio of 1.097. Thus, the black male population was the driving force for the overall decline in the male prison versus nonprison mortality ratio to below 1. The mortality ratio resulted from black males’ high mortality outside of prison, their comparatively low level while in prison, and the compositional contributions made to the two populations (i.e., the high mortality outside of prison for black males makes a smaller contribution to the whole than the low level in prison). These results document the importance of decomposing the population by race and sex.
As illustrated in the bottom row of , the difference between black and white males in prison disappears for the first and last periods. Outside of prison, black males lost at least twice as many years of life as white males. The top of this table shows the contrast in the male-female difference in mortality when we look at persons imprisoned versus those not in prison. The bottom portion shows the same outcome for race, but with much more striking results. In contrast to females and white males and despite significantly increased rates of mortality in prison in general, the mortality of black males in prison decreased significantly.
Black Males Exhibit Lower Mortality in Prison
Years of life lost both inside and outside of prison for black males increased in the second study period, 1990–1992, while it decreased for every other group. This finding is in alignment with the rise in death rates among black males between 1984 and 1989 due largely to rises in human immunodeficiency virus infection and homicide (Kockanek, Maurer, and Rosenberg 1994
). Indeed, the decrease in life expectancy observed during the late 1980s for black males did not follow the expected trajectory of increasing life expectancy that white males experienced. Consequently, the years of life lost ratio for white to black males displayed a significant departure from the results in the other two periods.
and permit a comparison of age-specific death rates and focus on age-specific differences among males in 1996–1998. In all of the study periods, mortality levels of the nonprison black male population were greater than both those of the white male non-incarcerated population and of the black prison population. In prison, the age-specific racial difference in mortality was smaller, and in the earlier period, black males had lower death rates (not displayed). Panels a–d in depict these two points, showing age-specific plots of log mortality by race and location.
Comparison of Male Mortality by Race and Location in United States, 1996–1998a
Age-Specific Mortality Ratio for Black Males, 1996–1998
Panel a of shows that, once again, black males in prison had lower levels of mortality at every age than the comparable nonprison population, and panel b shows that white males had lower mortality than black males at every age. Panel c illustrates that the age pattern of mortality for white males in prison and the general white population were virtually identical. Panel d shows similar levels of mortality among black and white prisoners. Further examination of the age-specific mortality ratios reveals that the age-specific rates were not significantly different from 1 for white and black male prisoners or for white nonprisoners and white prisoners. That is, black males in prison saw a mortality rate that corresponds to that of white males in the nonprison population.7
In contrast, an examination of the ratio of age-specific rates between black male prisoners and nonprisoners reveals that most rates are significantly different from each other. shows the ratio of the age-specific rates for black males for the last period, 1996–1998. The curve is lowest at younger ages, where there is an initial decline until age 22. Between ages 22 and 44, the curve steeply increases, but thereafter it displays a gradual decline through age 64. Thus, the main departure of the black prison population from the U.S. black population occurred in younger years of life; it gradually disappeared in the middle ages, but increased once again in the later ages. In other words, the greatest difference in the two populations occurred when homicide rates and accidents were highest and during the ages when morbidity and mortality increase.
Debunking the Safety Hypothesis
The findings suggest several hypotheses about these mortality differentials. The trends display a decrease in relative mortality levels between prisoners and nonprisoners and show that years of life lost were significantly higher for prisoners than for their nonprison counterparts for most of the groups studied, with the exception of black males. Lower mortality among black males could be attributed to a decline in the environmental risks—such as motor vehicle accidents and deaths related to firearms—that they would experience out of prison. Conditions in prison could simply be safer than those outside of prison for this segment of the population in particular. However, the following data analysis, which explores the impact of the absence of motor vehicle accidents and firearms on mortality, suggests that this hypothesis, which I call the “safety hypothesis,” is incorrect. The method and results of the safety hypothesis analysis are detailed below. Additionally, one might consider an alternate hypothesis: prison, an environment that appears to have a detrimental health impact on most groups, is still a healthier environment than that typically experienced by black males in the nonprison population.
Prisoners do not possess guns or have exposure to motor vehicles. Thus, certain causes of death that would normally arise are not present in the prison population. Among males, deaths from accidents, homicide, and suicide rank in the top 10 causes of death for all the years of study (National Center for Health Statistics 2007
). Accidents also rank in the top 10 causes of death for females (National Center for Health Statistics 2007
). Deaths related to motor vehicles make up the largest share of deaths due to accidents, ranging from 54% to 59% of all accidents (U.S. Department of Health and Human Services 1992a
). Firearms were involved in 54% to 57% of all suicides and 63% to 70% of all homicides (U.S. Department of Health and Human Services 1994a
). Thus, prisoners might fare better because of their limited exposure to certain types of accidents and firearms (U.S. Department of Health and Human Services 1999
I explored the validity of this safety hypothesis via two analyses. The first used the associated single decrement life table and posed the hypothetical question: how would mortality change in the nonprison population if deaths resulting from motor vehicles or firearms were removed? Let us call the hypothetical population resulting from the removal of these deaths the “safe population.” The second analysis explores the expected mortality of prisoners if they were not in prison.
In , I show that removal of deaths involving firearms and motor vehicles in the nonprison population caused the years of life lost to decrease. The years of life lost for males in the resulting “safe population” was 2.861 in the first period, which is 14% less than that of the total nonprison population and 24% less than the prison population. By the last period, however, the difference between the male safe and prison populations was smaller. The former had only 9% fewer years of life lost than the latter. In contrast, removing these categories of deaths had a different impact on females’ years of life lost. After these deaths were removed from the nonprison population, years of life declined by only 4%. The ratio of years of life lost in the safe population to the prison population began at 0.547 for females in the first period and rose to 0.834 by the last period of study.
Years of Life Lost Between Ages 18 and 65 in the U.S. Population When Excluding Deaths Due to Firearms and Motor Vehiclesa
The differences in mortality between the safe and total nonprison population were constant over time, even in separate comparisons by race. That is, the proportion of deaths occurring between ages 18 and 64 for which the underlying cause of death was related to a firearm or motor vehicle wavered very little from period to period.
The ratio of years of life lost between the safe and prison population, however, was very different for white and black males. In the first period, white males had a ratio of 0.647, while black males had a ratio of 1.535. After removing deaths due to accidents and firearms, the mortality of white males in the prison population converged closer to their safe counterparts, while black males’ mortality diverged. Moreover, in every period, the ratio of years of life lost in the black male safe versus prison population was greater than 1. Even when deaths from firearms and motor vehicle accidents were removed from the nonprison population, black male prisoners experienced a life expectancy benefit inside prison that the outside population did not.
The age-specific death rates of black males in the first and last periods further support the presence of a safety impact in prison. displays age-specific death rates for black males in prison, black males not in prison, and the black male safety population. As mentioned in the previous section, nonprisoner mortality in the black male population is greater than prisoner mortality at every age between 18 and 64. The curve for the safe population intersects with the curve for the prison population at younger ages and then gradually diverges, suggesting that in the younger years, a large proportion of the decrease in mortality is from limited exposure to vehicles and firearms. The proportion of deaths due to motor vehicles or firearms declines as age increases, lessening the distance between the safe and total nonprisoner curves.
Comparison of Black Male Mortality Under Various Conditions, 1996–1998
Thus far, in the description of my results, I have used the nonprison population as the central comparison. My study also examined the protection of prison walls and used the life table to examine potential mortality by adding deaths due to firearms and motor vehicle accidents to the prison population’s existing death count. Let us call this segment the “at-risk” population.8
As one might expect, the relative difference between the at-risk population and nonprison population was significant for most groups, but the opposite was true for black males. The ratio between the at-risk and prison populations was less than 1 for black males in each period. This finding suggests once again that the lower mortality experienced by black male prisoners results not only, or even primarily, from the prison’s protective shield.
Socioeconomic Status and Mortality Rates in Prison
How does the mortality of prisoners compare with that of other socioeconomic categories? This section answers that question using data from 1996–1998, combined with Molla, Madans, and Wagener’s (2004)
data addressing socioeconomic differentials in 1998. presents the mortality of males and females between the ages 25 and 64 by educational attainment. It describes the educational attainment of prisoners prior to their current admission into prison using data from the 1997 Survey of Inmates in State and Federal Correctional Facilities.9
divides the last completed year of education into three categories that are consistent with Molla et al.’s study: 0–8, 9–12, and 13 or more years of schooling. Those with a GED or high school diploma were included in the 9–12 years of schooling category. As shows, the majority of prisoners attained this level of schooling prior to their current admission.10
also shows that only 11% of males and 14% of females in state correctional facilities had postsecondary education.
Educational Attainment of Prisoners, and Years of Life Lost Between Ages 25 and 64 by Educational Attainment: Late 1990s
The next set of rows describes years of life lost for prisoners during the last period, 1996–1998, and for those in the U.S. population in 1998. The table partitions the latter (prisoners excluded) by years of schooling and provides 99% confidence intervals in brackets beneath the point estimates. The mortality of those with little schooling differs only slightly from those with 9–12 years of schooling. Males with 0–8 years of schooling lost 3.591 years of life, and those with 9–12 years of schooling lost 3.473 years. This difference is larger for females; those with 0–8 years of schooling lost 7.2% more years of life than females with 9–12 years of schooling.
The magnitude of the mortality difference between those with 9–12 years of schooling and those with postsecondary education is considerably larger, however. Between ages 25 and 64, males who had postsecondary education lost 1.397 years of life, compared with their counterparts with 9–12 years of education who lost 2.5 times more years of life. Females with 9–12 years of schooling lost 1.821 years of life, while those with postsecondary education lost 0.887 years of life between ages 25 and 64. Based on the educational composition of prisoners prior to admission in prison and the number of years lost by educational attainment in the U.S. population, I estimated an expected value for the number of years lost in the prison population between ages 25 and 64. The estimate is simply the sum of the educational-specific product of years of life lost and the composition of the prison population. Thus, the expected number of years lost for male prisoners is 3.264 years, 40% greater than the actual value. For females, the observed number of years lost is 13% higher than the expected value. Hence, the expected mortality of prisoners is actually higher than that experienced in prison, underlining the need to disentangle the components (e.g., access to health care and basic nutrition) of this widely used proxy in mortality analyses.