# Unbalanced Juvenile Justice

## Measurements

This page shows the calculations we used to measure disparities on this website and provides additional examples.

## Raw numbers

If you select raw numbers as your measurement, the website will display the actual number of youth in that category. For instance, in Texas in 2011:

- There were 1,305 youth of color detained on the one-day count (which is a snapshot of youth in detention).
- There were 25,531 youth of color admissions to detention (in the course of the full year).

## Rates

A rate is a quantity measured with respect to another quantity.

For this website, rates are calculated by dividing the number of youth involved in the juvenile justice system by either (i) the number of youth in the population or (ii) the number of youth involved at a prior decision-making point. The quotient is then multiplied by a number (for example 100,000 to give a “rate per 100,000.”)

### Rate based on youth in population

For example, one-day count data includes youth detained on a given day. The rate of detention in the U.S. per 100,000 Black youth in the population in 2011 is calculated as follows:

*Thus, on a given day in 2011, for every 100,000 Black youth age 10-17 in the United States, 168 were detained.*

### Rate based on prior juvenile justice decision-making point

In addition to calculating a rate per youth in the population, you may calculate the rate per prior decision-making point in the “decision-making points” section of the website.

Except for the point of arrest (which uses a rate per 1,000 youth in the population), the Relative Rate Index (RRI) calculates rates per 100 youth at the prior juvenile justice decision-making point. For example, detention rates are calculated per 100 referrals to court.

To calculate the detention rate for Black Youth in Fairfax County, VA in 2012, per 100 referrals to court:

*Thus, in 2012, for every 100 Black youth referrals to court in Fairfax County, VA, there were 17.2 admissions to secure detention.*

## Disparity gap

The disparity gap is a ratio of rates, or a “relative rate.” To calculate the disparity gap, divide the rates for White youth and Youth of Color:

When calculating the disparity gap, we compare each race and ethnicity to White youth. The rate of involvement for White youth is always the denominator. The “relative rate” for White youth is always 1, since we are comparing the rate for White youth to itself.

For this website, disparity gaps are calculated using either the (i) rate per youth in the population or (ii) rate per prior decision-making point.

### Disparity gap using rate per youth in population

To calculate the Disparity Gap in Rates of Detention for Black vs. White youth in the U.S. in 2011, using the rate per 100,000 in the youth population:

*Thus, on a given day in 2011, Black youth in the United States were 5.47 times as likely as White youth to be admitted to detention. The ratio is 5.47 to 1.*

### Disparity gap using rate per prior decision point

To calculate the Disparity Gap in Rates of Detention for Black vs. White youth in Texas in 2011, using the rate of detention based on 100 referrals to court:

*Thus, in 2011, Black youth in Texas who were referred to court were 1.13 timesas likely to be admitted to detention as White youth in Texas who were referred to court. The ratio is 1.13 to 1.*

## Using Multiple Measurements

As you experiment with the state data map on this site, you may notice that some of the smallest states have the highest rates of incarceration and/or disparity gaps. It is important to interpret these the data within context and use multiple measurements to understand the problem. This is best illustrated with an example.

In 2011, Wyoming had the fifth highest rate of detention for Black youth in the country (360 per 100,000 Black youth). In raw numbers, that represented only three youth. By comparison, California had the seventh highest rate of detention for Black youth in the country (337 per 100,000 youth). Yet, in raw numbers, that represented 1,008 Black youth--the highest number of Black youth detained in the nation.

All states should investigate disparities and work towards excellence and equity for youth in their systems. However, our example illustrates why it is also important to use multiple measurements to understand the problem. Although rates of detention for Black youth are similar in Wyoming and in California, the raw numbers of youth involved are very different, and may lead to different strategies for reform.