People in Jail in New York City: Daily Population Trends

The visualization below allows you to focus on a specific subgroup of the jail population and see how the number of people in custody has changed over time. For example, you can look at the number of people detained pretrial for drug charges broken down by race from July 1, 2018 to August 1, 2018. In order to see people of all statuses, you must select all statuses in the 'Select Status:' bar.

People in Jail in New York City: Length of Incarceration

The visualization below allows you to focus on a specific subgroup of the jail population in order to see how long people who are currently incarcerated have been held in DOC custody.

View Length of Stay Over Time

The following graph allows you to see how the length of incarceration for a specific subgroup of people who were discharged from DOC has changed over time. In order to get a better understanding of the trends over time you can choose to group the data by week or by month. If you choose by month, then the dots in the graph will show the average length of stay for all people who were discharged within a month. Given the large fluctuations in length of stay from day to day, it may be easier to view the data when grouped by week or month.

NYC JailViz 2.0 Application: Tracking New York City Jail Population Trends

In April 2017, following years of work by advocates and activists, Mayor de Blasio committed to closing the notorious Rikers Island jail. From a high of more than 21,000 people incarcerated on any given day in 1991, the city had already cut its incarceration numbers by more than half, while remaining the safest big city in the United States. But in order to close Rikers, city officials said, the numbers would have to drop by half again. NYC Jail Viz 2.0 provides a new way to track that progress.

Using data released daily by the New York City Department of Correction, the website allows people to see in real time who is incarcerated in New York City’s jails and why.

Information About the Data

The data presented in this application come from the New York City Open Data website. The New York City Department of Correction (DOC) updates this file daily to reflect the people that are currently in custody. The Vera Institute of Justice has been collecting this data since August 2017. The variables available in this file include race, age, gender, custody status, top charge, and Brad H status (a designation given to individuals who have met with mental health staff at DOC and are deemed to have at least some symptoms of mental illness). In some instances where the daily file was not available, we have recreated the daily information using admission and discharge files that are also available on the New York City Open Data website. The webpage consists of the following four tabs:

Daily Snapshot

The first tab provides an overview of the jail population on the most recent day that data is available. The graphs presented break down the jail population according to the information made available by the DOC. These variables include custody status, top charge severity, top charge class, top charge, race, age, gender, and Brad H status. Unfortunately, the DOC does not provide information on the ethnicity of those being held. You can also compare the most recent day to a day in the past. This option allows viewers to see whether particular populations have increased, decreased or remained steady over time. For example, you can compare today to two months ago and see the change in the number of people held pretrial or the number of people being held for a misdemeanor charge.

Daily Population Trends

The second tab allows you to filter the data in order to see the trends for a smaller group of people. In this section, you can choose the date range that you are interested in and choose from several variables to narrow down to a more specific group of people. This section makes it possible to choose from all the possible custody statuses, charges, and demographics. For example, you can look at the number of people who were detained pretrial for drug charges broken down by race. This part of the application makes it easier to estimate the potential effects of certain reforms as well as see how changes have influenced a certain group of people over time.

Admission Trends

The third tab is very similar to the second tab, except that instead of displaying the number of people in NYC jails each day it shows the number of people admitted to NYC jails each day. In order to make the data easier to understand over time, you have the option of grouping admissions by week or by month. This means that instead of seeing how many admissions there were on a specific day, you will see how many there were in a specific week or month. This can be more a more useful way of looking at trends over time due to the fluctuations that can occur in admissions on any given day.

Length of Incarceration

The fourth tab visualizes the lengths of stay for people currently held by DOC as well as the lengths of incarceration for people who have been released. While it is important to know how long people who are currently in jail have been incarcerated, it also important to look the average length of stay for everyone who has ever been incarcerated. This makes it easier to find out if the average length of incarceration for people who were admitted and discharged for a charge such as petit larceny has changed over the past year. The first graph provides data on the range of time that people currently incarcerated have spent in jail so far. The second graph allows you to see how the average length of stay for people released has changed over time. You have the option of grouping this data by week or by month in order to make the data easier to visualize. This may be useful if you are trying to find out whether reforms such as changes in discovery are having an impact on how long people are incarcerated pretrial. It may be hard to understand the trends over time when looking at day to day fluctuations, but much easier to see the broader story when viewing by week or by month.

Additional functions that might be useful

In the first tab you can download the figure and the data points used to create the figure by selecting the button on the top right of the graph. In the other tabs you can select the camera icon on the top right of the graph to download the figure.

You can hover on the figure and see the values of each data point. Place the cursor on a bar, slice or point to view a full sentence explaining the data.

You can view the graph showing the number of people in jail by race by rates instead of numbers. This enables you to know the number of people in custody per 100,000 people living in New York City to get a better understanding of racial inequity in jail incarceration.

Please email jailviz@vera.org with any questions.