Safe & Just Michigan acquired information from the Michigan Department of Corrections (MDOC) through the Freedom of Information Act (FOIA) last year. This data is a snapshot of everyone who was under the supervision of the Department of Corrections on October 30, 2018, so the information here may be different than our earlier blog describing the prison population. We are using this data to help us better understand who is incarcerated in Michigan prisons, why they are incarcerated, and for how long.  We will have a series of blogs related to understanding these questions.

Young and old alike

On the day the data was pulled, there were approximately 38,500 people incarcerated in Michigan prisons.

The average age of a person when they were sentenced to prison is about 32.5 years old. However, there is a large range. Of those incarcerated in 2018, the youngest person sentenced to serve time in prison was 13, while the oldest was 82 years old.

As to be expected, the current age of those incarcerated is a few years older, with a mean of almost 40 (39.91) years old. Again, we see a large range in ages, with the youngest person incarcerated at this time was 16 years old, and the oldest was 91 years old.

Looking at the first graph, we can see that for the two youngest age categories, there are more people being sentenced than are currently incarcerated. The category for 30-39 years old is almost even in the percent of those sentenced and those currently incarcerated. However, the proportions change after that. In the age groups from 40 and older, there are fewer people being and more who are currently incarcerated at that age.

This coincides with the plethora of research consistently showing that as people age, they are less likely to be involved in criminal behavior. Almost 50 percent of our prison population was under the age of 30 at sentencing, and more than 75 percent was under the age of 40 years old. Comparatively, only 26 percent of the prison population is currently under the age of 30, and 54 percent is under the age of 40.


Age at Sentencing & Current Age in Michigan Prisons

*May not equal 100% due to rounding.


Complexities of race and gender

Only 5.5 percent of Michigan’s prison population is female, which is close to the national average of 7 percent. This is a modest percentage of our prison population, but it is important to note proportion of women serving time in prison has increased nationally even faster than the whole prison population. In the last 40 years, the U.S. prison and jail population has grown 500 percent, while the number of women incarcerated has increased at a rate twice of that of men since 1980.

Unravelling the racial and ethnic characteristics of Michigan’s prison population is a complex task. The data collected by the MDOC and many other states only include race, not ethnicity, and most commonly only categorize people as “black” or “white.” Latino/Hispanic people are significantly undercounted. In fact, Michigan is one of 13 states that do not regularly include a category for Latino/Hispanic in their data.

The state is not consistent in how it categorizes and counts incarcerated people by their race or ethnic background. In one set of data known as the CMIS (Corrections Management Information System), people are described only as “white” or “not white,” while the Michigan Offender Tracking and Information System includes categories such as Black, Hispanic, Asian and other groups. Complicating matters, this data is not self-reported by the incarcerated people themselves but is estimated by MDOC employees, so there’s no way to be certain how accurate it may be.

Unfortunately, there are limited ways to get this information, short of going into facilities and asking each individual how they racially and ethnically identify. One attempt to work around this shortfall in data is information available through the US Census. As part of the American Community Survey five-year estimates, there is data available on populations who live in group quarters, such as nursing facilities, university housing and correctional facilities. One concern with using these estimates is they lump jail and prison populations together, which make it impossible to know if the jail and prison populations differ demographically. However, using this source of data, other estimates are available that otherwise we would not generally have access to such as veteran or disability status, or the percent who are able to speak English “very well.”

A Comparison of Race/Ethnicity Data in Michigan Correctional Facilities

*May not equal 100% due to rounding.


Comparing racial and ethnic data from the ACS five-year estimates and the MDOC data, the percentage of groups are similar. However, the ACS has categories that are not included in MDOC data. Interestingly, compared to the MDOC data, the ACS estimates about 6 percent fewer people incarcerated in Michigan are Black. This could be due to the inclusion of a “two or more races” category. Additionally, the percent of Hispanic/Latino almost tripled, from 2.3 percent according to MDOC data, to 6 percent from the ACS. The other area of difference was in what is listed as “other” in the graph above. For the MDOC data, “Other” includes Asian, Native American, Pacific Islander, and “unknown,” which totals about 2 percent of the prison population. The ACS data, on the other hand, includes American Indian/Alaskan Native, Asian, Native Hawaiian and other Pacific Islander, other race, and two or more races, which comprises 6 percent. While the differences between the two sources of data are not massive, the tripling of the Hispanic/Latino population and the “Other” category does raise concerns with correctional personnel determining an individual’s racial or ethnic identity.

Safe & Just Michigan believes that understanding who is in our prison is important.  In order to do this, there needs to be accurate and accessible data.  To ensure that, these individuals should be able to self-report and racial and ethnic categories should be consistent with the Census Bureau data collection standards.

~Anne Mahar
Research Specialist