The tragic stories pop up frequently in local media: a curious toddler gets hold of a gun and accidentally shoots himself or someone else. But how often does that happen? Under what circumstances? And what children are most at risk?

In a new investigative partnership, a team of reporters from the AP and USA TODAY Network spent six months seeking answers to those questions and others about accidental shootings involving minors. What they discovered is horrifying: A child dies every other day of an accidental shooting in the United States. What's more, the federal government significantly undercounts the problem.

The powerful investigation earns the Beat of the Week.

The project began after Brian Carovillano, vice president for U.S. news, made gun violence a key topic this year for the domestic news staff. There was already mutual interest between AP and USA Today in collaborating on major projects, given the reach and staffing of both news organizations. The guns project seemed a perfect fit for a joint effort. (This is the second recent investigative collaboration between the AP and another news organization, following an examination of the political influence of the opioids industry).

AP data manager Troy Thibodeaux contacted the Gun Violence Archive, a nonpartisan nonprofit that was attempting to catalog every shooting in America, based on public records and media reports. They agreed to give AP the information they were collecting. With that, AP and USA Today formed a team of reporters and data journalists to research each case. The focus for the initial story was accidental shootings involving kids.

The raw information from the Gun Violence Archive encompassed 140,000 shootings, and it included misspelled names, incorrect ages and other errors. Before the reporters' research could begin in earnest, data journalists Larry Fenn, Serdar Tumgoren and Meghan Hoyer had to puzzle through the technical details that would make the Gun Violence Archive data searchable and less overwhelming. Part of that solution involved applying an algorithm to analyze underlying patterns and determine which cases were within the scope of the project.

In the end, the reporters' comprehensive picture revealed more than 1,000 accidental shootings involving minors over a 2 1/2 year period. It showed that more than 320 minors age 17 and under and more than 30 adults were killed in such shootings. For the first six months of this year, those shootings claimed the life of a minor every other day.

"I sit there looking at these things and say, this should not be happening," a prosecutor said.

Startlingly, they also found that the limited statistics kept by the federal government significantly undercounted the problem. That such shootings spike at age 3 and again at ages 15 through 17 was one layer of detail the government does not track.

While numbers were a big part of the story, so were the people behind them. Lead reporter Ryan Foley of the AP State Government Team, along with AP national law enforcement reporter Lisa Pane and USA TODAY Network investigative reporter Nick Penzenstadler, spent months identifying cases that fit the trends identified in the data. Though heartbroken over their loss, parents of dead toddlers and teens across the country opened up to them.

One mother was so angry at the death of her young son that she decided to focus her outrage on lawmakers, demanding a state law that would require prosecutions for adults whose guns are used in accidental shootings. Another recalled watching her teenage son collapse on the floor in a pool of blood after a friend brought a handgun to their house and accidentally fired it. The boy she nicknamed "Chunks" as a baby was dead within hours.

As part of his reporting, Foley discovered that one rural county in Iowa had experienced three such shootings in the span of a year, causing grief and some soul-searching in the gun-loving region. "I sit there looking at these things and say, this should not be happening," the district attorney told him. Another sidebar, by Pane, explored the government’s limited research into accidental shootings and what might prevent them.

To complement the reporting, Fenn and Hoyer created a data set that could be shared with all AP customers for their own localizations. This was released in advance, and the results were spectacular: The package, edited by Jerry Schwartz of the Top Stories Desk, landed on at least 111 front pages. Mainbar: http://apne.ws/2dBguud One-county sidebar: http://apne.ws/2dR3MaP Government research sidebar: http://apne.ws/2dPGh3f

Some newspapers wrote their own stories from the local data and the background contained in the national stories. Some used state sidebars written by more than 20 AP bureaus.

PBS NewsHour produced a full segment on the package, including an on-air interview with Foley: http://www.pbs.org/newshour/videos/#195640 . In an editorial, The New York Daily News wrote: "This tally of bloodshed and lives lost is nowhere to be found anywhere in the vast storehouse of data kept by the U.S. government. Instead, the count is the product of more than six months of research by the Associated Press and the USA Today Network, working with the non-partisan Gun Violence Archive." http://nydn.us/2e44ovf

For their painstaking and hugely impactful work, Foley, Penzenstadler, Fenn and Pane win this week's $500 prize.

John Daniszewski