Reading over the list of 2016 Pulitzer Prize winners makes clear just how essential journalism’s watchdog role is to public health. In 2015, news organizations devoted considerable resources to researching, reporting, and commenting on slave labor in international seafood supply chains; funding cuts resulting in dangerous conditions in Florida mental hospitals; and failures in justice systems across the country. Bringing public attention to these problems is a first step to fixing them, and in many cases, this reporting has gotten results.

The Associated Press won the Public Service prize for their investigation into slave labor in Southeast Asia’s seafood industry. Over the course of 18 months, journalists found and spoke with enslaved workers and tracked the seafood they were forced to catch and process. They documented horrific conditions, including in shacks in Thailand where workers were forced to peel shrimp for 16 hours a day, and tracked the tainted seafood to suppliers of major US supermakert chains and popular brands of canned pet food. The attention spurred action from  seafood importers and buyers, as well as public officials. Months after the original stories ran, the AP’s Esther Htusan and Margie Mason reported, “More than 2,000 men from Myanmar, Thailand, Cambodia and Laos have been identified or repatriated since the AP’s initial story ran, according to the International Organization for Migration and foreign ministries.”

In the Investigative Reporting category, the prize went to Leonora LaPeter Anton and Anthony Cormier of the Tampa Bay Times and Michael Braga of the Sarasota Herald-Tribune for their series “Insane. Invisible. In danger.” on Florida’s state-funded mental hospitals. They reported on the impacts of $100 million in budget cuts and a policy change that allowed the hospitals to stop reporting many injuries. As a result, the staff-to-patient ratio dropped, so that employees were often left alone to oversee 15 or more men with mental illnesses. These conditions were unsafe for the guards as well as the patients, and the reporters that nearly 1,000 injuries attacks occurred over the course of six years, though the state agency stated there were only 450. Last month, Cormier and Braga reported a positive outcome from their series: “After years of drastic cuts, Florida’s mental hospitals stand to get as many as 160 new workers under a budget proposal approved this week by state lawmakers.”

Winners in multiple categories shed light on failures — and, in one case, a success — in the justice system. The Pulitzer Prize for Explanatory Reporting went to T. Christian Miller of ProPublica and Ken Armstrong of The Marshall Project for “An Unbelievable Story of Rape,” which exposed “law enforcement’s enduring failures to investigate reports of rape properly and to comprehend the traumatic effects on its victims.” After 18-year-old Marie reported being raped in Washington stae, police confronted her about inconsistencies in her story; she then recanted, and was charged with filing a false report. In Colorado, however, a team of detectives from different cities collaborated to catch a serial rapist, who turned out to have raped Marie and 27 other women.

The Washington Post staff won in the National Reporting Category for “its revelatory initiative in creating and using a national database to illustrate how often and why the police shoot to kill and who the victims are most likely to be.” The Post created a database with details on what ended up being 990 fatal police shootings in 2015 and reported on some of the patterns, including that many of the victims were people with mental illnesses, and that although white men made up the largest share of the victims, “black men were seven times more likely than white men to die by police gunfire while unarmed.”

In Editorial Writing, John Hackworth and Brian Gleason of Sun Newspapers, Charlotte Harbor, FL won for their “fierce, indignant editorials that demanded truth and change after the deadly assault of an inmate by corrections officers.” The assault in question was that of Matthew Walker, who was beaten by a group of correctional officers at Charlotte Correctional Institution. A public outcry followed the barrage of critical stories and editorials, and eventually eight of the 10 involved guards were fired or quit.

When existing safeguards aren’t enough to ensure fair and safe conditions, watchdog journalism is essential for identifying problems and spurring corrective action. Public health needs strong media organizations, at both the local and national levels, to play this watchdog role. This is one of the reasons I subscribe and donate to multiple media organizations (including the Washington Post and ProPublica).

Congratulations to all of the Pulitzer Prize winners and finalists, and to their colleagues and organizations. You can view them all here.