In the past few years, there have been drops in the correctional population as a whole as well as drops in the incarceration rate. There have also been changes in the reported racial and ethnic demographics of the people in prison in the US. Unfortunately some of the statistics and analysis floating around can be misleading, especially when only some selected data are shown and presented out of context.

The federal Bureau of Justice Statistics recently released its report, Correctional Populations in the US 2014. We'll start there, with Table 1 and Table 2.

These data show that the total correctional population in 2000 was 6,467,800 - that's prison, jail, parole, and probation – or 2,280 per 100,000 population (all ages). In 2014, the total correctional population was somewhat higher -- 6,851,000 -- yet the rate was somewhat lower: 2,140 per 100,000 population (all ages).

That's partly because the estimated US population has grown since 2000. Incarceration rates are measured using the Census Bureau's population measure, specifically as BJS notes in the CPUS report in Table 2, page 3: “U.S. Census Bureau, postcensal estimated resident population for January 1 of the following year, 2001, and 2006–2015.”

According to the Census Bureau, the US population in 2000 was 281,421,906.
http://factfinder.census.gov/faces/tableservices/jsf/pages/productview…
By 2010, the US population had grown to 303,965,272.
http://factfinder.census.gov/faces/tableservices/jsf/pages/productview…
The Census Bureau estimated that the US population in 2014 was 314,107,084.
http://factfinder.census.gov/faces/tableservices/jsf/pages/productview…

The total correctional population peaked in 2007, then started a decline, though it was still larger in 2014 than it was in 2000. The number of people under correctional supervision per 100,000 US residents of all ages also peaked in 2007, at 2,420 per 100,000, then started a decline. Yet because the total overall population was growing, the drop in that rate was much greater than the drop in the number of people in the correctional population. That why in 2010, though the correctional population was over 7 million, we had the same rate of 2,280 per 100,000 that we had back in 2000, when the total correctional population was less than 6.5 million.

Let's look now at prisons, jails, and the overall incarceration rate (and I'm using “incarceration” correctly here, including both prisons and jails; when it's prison only, the term of art these days is “imprisonment rate”). In 2000, there were 1,945,400 in prisons and jails, for a rate of 690 incarcerated per 100,000 population (all ages). In 2014, there were 2,224,400 incarcerated, yet the incarceration rate was still 690 per 100,000 population (all ages). More people in prison, yet the rate remains the same. Again, changes in the overall population have an impact. That's why it's important to look at all the numbers. A partial examination only tells part of the story.

Another part of the current prison narrative is that we have proportionately more people these days who identify as white behind bars than we had 15 years ago, and proportionately fewer African Americans. Yet, do these numbers hold up?

First, let's correct an assumption that the Post makes in its headline for that piece by Professor Humphreys: "There’s been a big decline in the black incarceration rate, and almost nobody’s paying attention." Not true. The trend was noted by the federal Bureau of Justice Statistics almost a decade ago, and the data are presented in the Race & Prisons section of Drug War Facts. This is from the Prisoners in 2006 report by BJS:

"Declining percentage of blacks among sentenced prisoners
"Comparisons of changes in the racial composition of prison populations over time are constrained by new data collection methodologies. Following guidelines provided by the Office of Management and Budget, beginning in 2005 BJS estimated racial composition of the prison population separately for persons identifying with one race (97%) and those identifying with two or more races (3%). These guidelines have reduced the number and percent of persons identified as non-Hispanic white and non-Hispanic black prisoners. In addition, administrative data on the race and Hispanic origin of prisoners reported to BJS by corrections officials also overstate the number of non-Hispanic white and black prisoners and understate the number of Hispanics and persons of two or more races.2
"Both administrative and estimated data indicate an overall decline among black prisoners from 2000 through 2006. The 2006 administrative data show a decline from 46.2% to 41.6%, while the estimated data indicate a decline from 42.4% to 37.5% (table 8)."
"2 Some jurisdictions are not able to report Hispanics or persons of two or more races as a separate category as requested under OMB guidelines."
William J. Sabol, PhD, Heather Couture, and Paige M. Harrison, "Prisoners in 2006" (Washington, DC: US Dept of Justice Bureau of Justice Statistics, Dec. 2007), NCJ219416, p. 7.
http://bjs.gov/content/pub/pdf/p06.pdf

Note that the Bureau does more than just report the numbers, they're also giving some indications of how those numbers came about: changes in how people are identified and classified racially and ethnically, as well as changes in the overall population.

Let's look at the prisoner numbers for 2000 and 2014, noting the changes, then do some math.

In 2000, there were a total of 1,237,469 men in prisons (and since that article only looks at prisons, I'll stick with those), of which 436,500 were white, 572,900 were African American/black, and 206,900 Latino/Hispanic, leaving 21,169 for whom no race or ethnicity is reported; and a total of 83,668 women, of whom 34,500 were white, 37,400 were African American/black, 10,000 were Latino/Hispanic, leaving 1,768 for whom race or ethnicity is reported.

Number of sentenced prisoners under State or Federal jurisdiction, by gender, race, Hispanic origin, and age, 2000
Number of sentenced prisoners
Males Females
Totala Whiteb Blackb Hispanic Totala Whiteb Blackb Hispanic
1,237,469 436,500 572,900 206,900 83,668 34,500 37,400 10,000

Note: Based on custody counts from National Prisoners Statistics (NPS-1A) and updated from jurisdiction counts by gender at yearend. Estimates were rounded to the nearest 100.
a Includes American Indians, Alaska Natives, Asians, Native Hawaiians, and other Pacific Islanders.
b Excludes Hispanics.
Beck, Allen J., PhD, and Harrison, Paige M. Prisoners in 2000. Washington, DC: US Dept of Justice Statistics, Aug. 2001, NCJ188207, Table 14, p. 10, and Table 15, p. 11.
http://www.bjs.gov/content/pub/pdf/p00.pdf

Number of sentenced prisoners under State or Federal jurisdiction per 100,000 residents, by gender, race, Hispanic origin, and age, 2000
Number of sentenced prisoners per 100,000 residents of each group
Male Female
Totala Whiteb Blackb Hispanic Totala Whiteb Blackb Hispanic
904 449 3,457 1,220 59 34 205 60

Note: Based on estimates of the U.S. resident population on July 1, 2000, and adjusted for the 1990 census undercount.
a Includes American Indians, Alaska Natives, Asians, Native Hawaiians, and other Pacific Islanders.
b Excludes Hispanics.
Beck, Allen J., PhD, and Harrison, Paige M. Prisoners in 2000. Washington, DC: US Dept of Justice Statistics, Aug. 2001, NCJ188207, Table 14, p. 10, and Table 15, p. 11.
http://www.bjs.gov/content/pub/pdf/p00.pdf

In 2014, there were 1,402,404 men in prisons, of whom 453,500 were white, 516,900 were African American/black, 308,700 were Hispanic, and 123,300 were "other" (which totals 1,402,400 people, probably due to rounding), and a total of 106,232 women, of whom 53,100 were white, 22,600 were African American/black, 17,800 were Latino/Hispanic, and 12,800 were "other" (which totals 106,300 people, presumably due to rounding).

Number and imprisonment rates of sentenced state and federal prisoners per 100,000 U.S. residents, by demographic characteristics, December 31, 2014
Male Female
Age group Totala All malea Whiteb Blackb Hispanic Otherb All femalea Whiteb Blackb Hispanic Otherb
Totalc 471 890 465 2,724 1,091 968 65 53 109 64 93
Number of sentenced prisonersd 1,508,636 1,402,404 453,500 516,900 308,700 123,300 106,232 53,100 22,600 17,800 12,800

Note: Counts based on prisoners with sentences of more than 1 year under the jurisdiction of state or federal correctional authorities. Imprisonment rate is the number of prisoners under state or federal jurisdiction with a sentence of more than 1 year per 100,000 U.S. residents of corresponding sex, age, and race or Hispanic origin. Resident population estimates are from the U.S. Census Bureau for January 1, 2015. Alaska did not submit 2014 data to the National Prisoner Statistics (NPS), so totals include imputed counts for this state. See Methodology.
a Includes American Indians and Alaska Natives; Asians, Native Hawaiians, and other Pacific Islanders; and persons of two or more races.
b Excludes persons of Hispanic or Latino origin.
c Includes persons age 17 or younger.
d Race totals are rounded to the nearest 100 to accommodate differences in data collection techniques between jurisdictions.
Sources: Bureau of Justice Statistics, National Prisoner Statistics, 2014; Federal Justice Statistics Program, 2014; National Corrections Reporting Program, 2013; Survey of Inmates in State and Federal Correctional Facilities, 2004; and U.S. Census Bureau, postcensal resident population estimates for January 1, 2015.
Carson, E. Ann. Prisoners In 2014. Washington, DC: US Dept of Justice Bureau of Justice Statistics, Sept. 2015, NCJ248955, Table 10, p. 15, and Appendix Table 3, p. 29.

Notice the difference in the number, and proportion, of individuals classified by the criminal justice system as "other." The number of men in prison who identify as "other" grew by about 500% between 2000 and 2014, going from 21,169 to 123,300. Same with the number of women in prison, the "other" category growing from 1,768 in 2000 to 12,800 in 2014, an increase of more than 600%. The most likely explanation is that a lot of people who would have been identified as either African American, Latino, or white in 2000 are now being identified differently.

For additional perspective, and to see how data can be manipulated to create the illusion of change in the criminal justice system, here are the data on US correctional populations in 1990:

Estimated number of adults on probation, in jail, in prison, or on parole and their percent of the adult population, by sex and race, 1990
Sex Race
Totala Male Female White Black Other
Total 4,349,817 3,747,949 601,868 2,666,484 1,633,570 49,763
Probation 2,670,234 2,189,592 480,642 1,815,759 827,773 26,702
Jail 403,019 365,821 37,198 205,540 189,419 8,060
Prison 745,157 703,642 41,515 368,853 366,617 9,687
Parole
531,407 		488,894 42,513 276,332 249,761 5,314
U.S. adult resident
populationb 		185,105,000 88,614,000 96,491,000 158,398,000 20,773,000 5,934,000
Percent under correctional
care or in custody 		2.3% 4.2% 0.6% 1.7% 7.9% 0.8%

Note: Detail may not add to total because of rounding. In cases where sex or race was unknown or not reported, percentages were applied based on known cases.
a A small number of Individuals may have multiple correctional statuses; consequently, the total number of persons under
correctional supervision may be an overestimate. See technical note.
b Resident population 18 years or older on April 1. 1990.
Jankowski, Louis W. Correctional Populations in the United States, 1990. Washington, DC: US Dept of Justice Bureau of Justice Statistics, July 1992, NCJ134946, Table 1.2, p. 6. https://www.ncjrs.gov/pdffiles1/Digitization/134946NCJRS.pdf

Male prIsoners under State or Federal Jurisdiction, by race, 1990
Total Male Prisoners 12/31/90 White Black American Indian/Alaska Native Asian/Pacific Islander Not Known
730,141 348,404 345,940 5,847 2,645 27,305

Jankowski, Louis W. Correctional Populations in the United States, 1990. Washington, DC: US Dept of Justice Bureau of Justice Statistics, July 1992, NCJ134946, Table 5.7, p. 84. https://www.ncjrs.gov/pdffiles1/Digitization/134946NCJRS.pdf

Female prisoners under State or Federal Jurisdlction, by race, 1990
Total Female Prisoners 12/31/90 White Black American Indian/Alaska Native Asian/Pacific Islander Not Known
40,646 19,426 19,269 396 164 1,391

Jankowski, Louis W. Correctional Populations in the United States, 1990. Washington, DC: US Dept of Justice Bureau of Justice Statistics, July 1992, NCJ134946, Table 5.8, p. 85. https://www.ncjrs.gov/pdffiles1/Digitization/134946NCJRS.pdf

Prisoners under State or Federal Jurlsdlctlon, by gender and Hispanic origin, 1990
Total All Genders Male Female
Total state and federal prisoners 12/31/1990 Hispanic Non-Hispanic Not Known Male state and federal prisoners 12/31/1990 Hispanic Non-Hispanic Not Known Female state and federal prisoners 12/31/1990 Hispanic Non-Hispanic Not Known
758,710 103,065 494,395 176,915 730,141 97,927 464,497 167,717 44,234 5,138 29,898 9,198

Jankowski, Louis W. Correctional Populations in the United States, 1990. Washington, DC: US Dept of Justice Bureau of Justice Statistics, July 1992, NCJ134946, Table 5.9, p. 86. https://www.ncjrs.gov/pdffiles1/Digitization/134946NCJRS.pdf

Sources for data and tables presented above, unless otherwise indicated:
Carson, E. Ann. Prisoners In 2014. Washington, DC: US Dept of Justice Bureau of Justice Statistics, Sept. 2015, NCJ248955, Table 10, p. 15, and Appendix Table 3, p. 29.
http://www.bjs.gov/index.cfm?ty=pbdetail&iid=5387 http://www.bjs.gov/content/pub/pdf/p14.pdf
Kaeble, Danielle, Maruschak, Laura M., and Bonczar, Thomas P. Probation and Parole in the United States, 2014. Washington, DC: US Dept of Justice Bureau of Justice Statistics, Nov. 2015. NCJ249057, Table 4, p. 5, Table 6, p. 7, and Table 1, p. 2.
http://bjs.gov/content/pub/pdf/ppus14.pdf
Beck, Allen J., PhD, and Harrison, Paige M. Prisoners in 2000. Washington, DC: US Dept of Justice Statistics, Aug. 2001, NCJ188207, Table 14, p. 10, and Table 15, p. 11.
http://www.bjs.gov/content/pub/pdf/p00.pdf
Jankowski, Louis W. Correctional Populations in the United States, 1990. Washington, DC: US Dept of Justice Bureau of Justice Statistics, July 1992, NCJ134946, Table 1.2, P. 6. https://www.ncjrs.gov/pdffiles1/Digitization/134946NCJRS.pdf