Prison Population in the United States: 1980-2015

A few months ago I read 'Just Mercy' by Bryan Stevenson. An intense and thought provoking book about incarceration, death row, and the power of justice and mercy for all, but particularly for the poor and defenseless. Soon after finishing the book, I was browsing statistics about prisons, facilities, inmates, etc. at various sites, particularly, The Bureau of Justice Statistics. Around the same time, health expert and statistician, Prof. Hans Rosling passed away. His GapMinder software was a disruptive tool in the field of data visualization, particularly health and developmental economics. I really just wanted to put something together connecting the works of both these wonderful visionaries.

I made this animation to see a trend of prisoners under the jurisdiction of state or federal correctional authorities in the United States. All this data is curated from the yearly bulletins available at the Bureau of Justice Statistics. 

How does the prison population look like in a Gapminder motion?

There are some interesting key points and events to note- 

• In 1999, roughly 0.5% of the US resident population was under state and federal correctional facilities. That was about 1.36 million men and women. 
• In 2001, the population grew at 1.1%, which was the lowest rate then, since 1972.
• In 2002, it was 1.44 million - a growth of 2.6% for the year.   
• In 2008, the number of inmates grew at the slowest rate of 0.8%, reaching about 1.61 million. 

• Subsequently, in 2010, the total prison population declined for the first time. This was due to two reasons - prison releases exceeded prison admissions and the resident population of the country increased in 2010, leading to a marginal decrease of 0.3% in prison population. During 2010, 31 states had fewer admissions, led by large states like California, Florida, Illinois, and Ohio. The decline was also offset by increased admissions in some states like Texas and Louisiana. 
• 2011 saw a decrease in total inmates for the second time, this time by 0.9%. The number of releases from state and federal prisons exceeded the number of admissions. This decrease was led mainly by the California Public Safety Realignment (PSR), wherein the Supreme Court upheld a lower court ruling that California must bring down its prison population to ~137% of design capacity to avoid overcrowding. In response to this, California State legislature and Governor enacted laws to reduce the inmates in state prisons beginning October 2011. 
• The three year decline in prison population stalled in 2013, with state and federal correctional facilities holding about 1.57 million inmates during the end of that year. About 3% of all male black residents in the United states were imprisoned in year end 2013, compared to 0.5% of white males during the same time. 
• 2014 again saw a decline in prison inmates by 1% from year end 2013. The decline was mainly due to fewer admissions. A third of the total decline occurred in the federal system. 
• The decrease in prison population from 2014 to 2015 was similar to the decrease that occurred in 2011 due to PSR in California. With the commitment of US Department of Justice to reduce nonviolent drug offenders, the federal prisons released such inmates in 2015 resulting in a decline. Several states also took measures to reduce overcrowding by reducing drug and property offenses from felonies to misdemeanors. Others adopted avenues such as re-entry programs, substance abuse treatment facilities etc. to reduce prison population. 

Inmate Population by Gender
Women inmates have typically been only a fraction of the male prisoners each year. From 1980 to 2015, the number of women inmates went from 3.9% to total to 7.3% of total. The number of women inmates peaked at ~115k in 2008 and declined marginally thereafter. So the bubble depicting women inmates is pretty much at the bottom of this plot throughout this time period. 

Some other questions I plan on addressing

I have additional inmates data by region (NorthEast, Midwest, South, and West), and race. I also have death row data for last thirty years or so. I hope to turn these into visualizations very soon.   

Note: 

1) Percentage population in prison includes prisoners under the jurisdiction of state or federal correctional authorities divided by the resident population of the country during that year. This does not include people in parole or probation. 

2) For 1980 to 1989 total inmate count and count by gender includes only sentenced prisoners - those that are sentenced to more than one year. 

3) I tried using the rosling.bubbles function in R, but unfortunately had difficulty getting it to work. So these images have been plotted in RStudio and then stitched up into a movie using ImageJ.