Last month, New York prison officials introduced a policy to effectively suppress prison journalism. It went unnoticed for a few weeks until reporters at New York Focus caught wind of it. A righteous backlash ensued, forcing the department to rescind the policy for the time being.

The incident left many people wondering: how common are restrictions on prison journalism? Building on data compiled by the Prison Journalism Project, we scoured handbooks, prison policies, and laws governing every corrections department in the U.S. to try and find out.

We found that while explicit bans on prison journalism are rare, a web of complex and vague policies make the practice extremely difficult and sometimes risky.

Prisons don’t want you to know what happens inside. That’s what makes prison journalism so important. As more news outlets publish incarcerated journalists, more departments will consider policies to control what information makes it out into the world.

The Federal Bureau of Prisons is the only agency we found that explicitly forbids any incarcerated person from acting “as a reporter.” But they are not alone in suppressing prison journalism.

For starters, the standard prison practice of censoring and surveilling snail mail, electronic messages, phone calls, and video visits violates basic principles of free expression and privacy. These principles are central to a journalist’s ability to maintain sources, work closely with editors, and report the news without interference. Only 4 states — Arkansas, Georgia, Michigan, and Texas — treat correspondence with the news media as “privileged communication,” meaning that letters between an incarcerated person and a media outlet cannot be opened or read by prison staff (although they may be searched in the presence of the incarcerated person for contraband).

However, the other 46 states and the federal government maintain the right to read and censor communications with the media. These policies are broadly explained as important to maintaining “security and order” — a vague justification left to the discretion of prison officials.

Read the full article about prison journalism by Brian Nam-Sonenstein at Prison Policy Initiative.