Advocates to Census Bureau: Stop making it harder for states to end prison gerrymandering

Census Bureau should stop its one-size-fits-all approach to privacy protections and refrain from adding “noise” when it reports the number of incarcerated people; states need accurate counts to end prison gerrymandering

by Aleks Kajstura, August 26, 2024

Last week the Prison Policy Initiative and Common Cause sent a letter to the Census Bureau urging it to publish data in a way that makes it easier for states to end prison gerrymandering.

Prison gerrymandering is a problem created because the Census Bureau incorrectly counts incarcerated people as residents of their prison cells rather than their home communities. As a result, when states and local governments use Census data to draw new political boundaries, they inadvertently give residents of districts with prisons greater political clout than all other residents.

After the 2020 count, the Census Bureau added another wrinkle to prison gerrymandering reform by taking a new approach to its data privacy protections that unintentionally made it harder for states to adjust their redistricting data to count incarcerated people at home. Every decade, the Bureau’s privacy protections ensure that no single person can be identified in the census data, and that everyone’s answers on the census forms remain private. This privacy guarantee is a statutory requirement, but the Census Bureau is free to achieve this privacy through whichever method it sees fit.

For the 2020 Census, the Bureau picked a new privacy method called differential privacy, which injects “noise” into the population data published by the census. This “noise” essentially takes the correctional facility populations and adds or subtracts a statistically-determined number of people in the population data published for the census. This had the consequence of undermining states’ efforts to address prison gerrymandering, as the letter explains:

There are 19 states that have formally addressed prison gerrymandering, these states account for nearly half (49.6) of the US population.

Although the approaches to population adjustments differ among the 19 states, they all rely on accurate counts of correctional facility populations to adjust redistricting data to avoid or limit prison gerrymandering.

In each case, the Bureau’s application of privacy protections added an unnecessary impediment to their data adjustment efforts. Facility populations are public. In most states, they are published – along with other demographic statistics – on state websites.

The letter concludes by asking the Bureau to stop undermining state efforts to end prison gerrymandering:

The Bureau should update its residence criteria to count incarcerated people at home. But if the Bureau continues to count all incarcerated people as if they were residents of the correctional facility they happen to be held at on census day then the correctional facility populations should be held invariant (or kept unchanged) to decrease the burden on the states that are correcting their redistricting data to count incarcerated people at home or last known address.

For more details, check out the full letter here (PDF).