For Charles Addington, policing is a numbers game.

He knew the numbers that described the task ahead of him in October 2009: Four reservations, covering 2 million acres. A mandate to cut violent crime by 5 percent.

He knew the odds against him: Violent-crime rates on Indian reservations are twice as high as those of the rest of the nation, and these four were among the 10 most violent in the country.

He had two years to get the job done.

So he looked to more numbers. Such as the numbers that spelled out patterns in crime that the tribal police forces had never analyzed before. Such as the paltry number of police officers who worked on the expansive reservations.

And at the end of those two years, there were new numbers, and those numbers spoke clearly: Addington had exceeded his target by leaps and bounds. He had cut violent crime by 35 percent.

For that massive achievement in tackling violent crime on reservations, Addington has been named one of this year’s nominees for the Samuel J. Heyman Service to America Medals, the prestigious awards for federal employees colloquially known as the Sammies.

A member of the Cherokee Nation from Jay, Okla., Addington joined his local police department in 1989, then went to work for his tribe soon after. He rose through the ranks of Indian law enforcement, eventually supervising police in six states from his post in Billings, Mont.

He made a habit of looking at past crimes to try to address their causes.

“If you’re always being reactive, you’re never going to fix the problem. Sometimes it’s not a law enforcement issue. It’s an economic issue. It’s a social issue,” he said, speaking of the high unemployment rates and rampant alcoholism that contribute to violence on reservations. “It always goes back to the past. . . . In Indian country, there’s a lot of history.”

In 2009, Addington got the summons to come to Washington.

During the two-year initiative on violent crime that brought him here, Addington made use of many of the same strategies he had employed in his years on the beat.

Aware that many residents mistrust police, he suggested that police departments on the four reservations in the program host community events, such as handball and basketball games, so that residents young and old might come to see police in a positive light — a plan he had used when he was working for the Cherokee police.

He had found in his role in Montana that a notice posted on the door of a business recording the last time an officer on patrol checked in at the establishment reassured proprietors and deterred burglars. He recommended that the four jurisdictions try similar visibility tactics.

In weekly phone calls, he brought people in each reservation together to talk about which approaches worked best.

He also offered the local police chiefs information that they had not previously scrutinized. By compiling data, he noticed that crime spiked at the time of certain powwows and other large celebratory gatherings. The local police forces made sure to park near those gatherings with their lights on.

Above all, Addington focused on bringing in more officers. “We knew from the very beginning that the numbers [would be] the key to being successful. You’ve got to get people on the ground to start making a difference,” he said. One of the reservations in his project, Wind River in Wyoming, had just eight police officers manning an area larger than the state of Delaware. To meet the national average for officers in a rural area of that size, it would need four times as many.

Addington started an aggressive recruitment effort across the country to entice aspiring police officers to take jobs on rural reservations. But he wasn’t content to wait the six months it would take to hire a complete staff. He turned to the secretary of the interior and even the White House to seek permission to borrow officers. With staff members on loan from the National Park Service, the U.S. Fish and Wildlife Service and other bureaus, he started fighting crime right away.

Pam Haze, a deputy assistant interior secretary, recalled that when the effort started, even 5 percent seemed a challenging goal. “At the time, we thought 5 percent was pretty aggressive,” she said. “We were surprised by the high levels of accomplishment.”

That the ultimate outcome was seven times better than demanded was in large part thanks to Addington, she said. “Charles is very hard working, very dedicated, very committed. He puts in a lot of extra effort and a lot of extra hours.”

Jason Thompson, who worked with Addington in Oklahoma and is now a colleague in the Bureau of Indian Affairs in Washington, agreed. “He’s just a doggedly determined individual,” Thompson said of Addington. “He doesn’t let the stumbling blocks or the hindrances that occur for all of us be the end of the road for him.”

Thompson praised Addington for always keeping front-line officers in mind. “He’s a cop. It doesn’t make any difference whether he’s at headquarters or in a patrol car,” Thompson said. “As we come up with ideas and strategic planning, as we do at headquarters, Charlie makes sure we don’t lose sight of uniformed men and women out in Indian Country.”

Wearing a business suit in the muraled hallways of the Interior Department, Addington speaks most enthusiastically about the efforts of those officers in uniform. He praises staff members who have spent their days off painting residents’ homes for free and organizing coat drives for local children.

He would like to return eventually to Oklahoma, where his wife lives on their cattle farm with his three stepchildren, two of whom are in grade school. But after the initiative concluded in September 2011, he signed on for a longer job with the Bureau of Indian Affairs’ Office of Justice Services.

As soon as the program ended, the bureau added two more reservations for the next two-year phase. And last year, Addington helped release a handbook for all tribal police forces on proven practices, such as those he has implemented successfully.

Officers such as the community-minded volunteers who paint and gather coats — and the encouraging numbers — keep him looking for more to do in Washington.

“We’re seeing change,” he said. “When you start seeing that you’re making a difference, you want more.”