NEW YORK -- David Stern responded to a report on NBA referees Thursday by vowing to build the "most effective possible system" to monitor illegal gambling and preserve the game's integrity.
The commissioner ordered the investigation last August after former referee Tim Donaghy was accused of betting on games he officiated and providing inside information to gambling associates to win their bets. Donaghy began serving a 15-month sentence on Sept. 23 at a federal prison in Pensacola, Fla.
Stern promised to implement all the recommendations included in former federal prosecutor Lawrence Pedowitz's review of the NBA's referees operations department, the result of a 14-month probe that cost the league several million dollars.
"We will be up there with the very best. No one will have a better system than we do," Stern said on a conference call. "But all of that said, to the idea that, you know, criminal activity will exist every place else in the world except in sports is just something that we can't guarantee. But we're going to have the most effective possible system that's ever been devised."
The report recommended it include: a hotline to anonymously raise questions about gambling and game integrity issues; making available any complaints the league receives about refs -- beginning in the 2008-09 playoffs -- to both teams to avoid suspicions of bias; requiring officials to annually report their contacts among players and team personnel to the league so it can monitor fraternization.
The league already has made a number of changes, including restructuring its referees operations department and posting officiating assignments the morning of games.
The report also suggests mandatory gambling education for players.
"We believe that gambling can expose the players and the league to significant risks, and therefore it is important that players be educated regarding those risks," the report said.
The 116-page document disputed Donaghy's allegations of specific misconduct and favoritism toward certain players and teams, but warned "because the potential for referee bias remains a threat to the integrity of the game, the league can do more."
It agreed with the federal government that there was no evidence Donaghy made any calls to affect the outcome of games after studying his work in 17 of them, including 16 during the 2006-07 season in which it was believed Donaghy made picks.
It also backed the government's stance that referee Scott Foster wasn't involved in any of Donaghy's misconduct. Donaghy called Foster 134 times from October 2006 to April 2007, but the FBI and Pedowitz were satisfied that Foster's description of their relationship as longtime friends provided a reasonable explanation for the calls.
"The report speaks for itself," said Lamell McMorris, spokesman for the referees' union.
Boston Celtics players Paul Pierce and Ray Allen endorsed the recommended mandatory gambling education.
"Throughout the years we have a number of different meetings. A gambling meeting wouldn't hurt," Allen said from training camp in Newport, R.I. "I think it's just as important to educate the guys to make sure they don't give money away that you've worked hard for and you want to continue to work hard for. The education would definitely help."
Pedowitz said that if he owned a team, he wouldn't even want his players taking part in card games on the team plane.
"The sickness of compulsive gambling can affect many people," Pedowitz said. "We have a concern that the culture of the NBA ought to be a disciplined one. So we worry about players."
New York Knicks guard Jamal Crawford said he didn't think gambling was a problem in the league.
"No, I don't think a lot of players gamble, if any," Crawford said. "We're pretty aware of it, but a class wouldn't hurt at all."
Stern wants to be sure players realize the dangers of being involved with people connected to gambling, as Donaghy was.
"It's really about who they are with and what information they give, because gamblers are always looking for an edge," Stern said. "And that's the concern that we have begun to address in rookies and we'll do more of with respect to players."
Stern already was aware through Pedowitz's interviews that nearly all his referees had violated some form of the gambling rules, though none of their activities reached the criminal level.
Referees are now allowed in the offseason to bet at a racetrack, off-track betting establishment or a casino -- though still not the sports book. However, a referee must notify the league's security department within 24 hours of placing such a bet.
Stern has asked Pedowitz to review the new program at the end of the season.
Retired Army Major Gen. Ronald L. Johnson, who served 32 years in the Army, was hired over the summer as senior vice president of referee operations in response to the investigation. Longtime ref Bernie Fryer became the NBA's vice president and director of officials, and Joe Borgia was appointed vice president of referee operations.
On Thursday, Pedowitz praised the choice of Johnson, who will address the complaints teams have about the performance -- and in some cases, perceived bias -- of certain officials.
"It's clearly an issue if the teams have a perception," Pedowitz said. "If it's there, it should be dealt with."
The report found no evidence to back Donaghy's accusations that specific games were manipulated, including playoff series in 2002 and 2005. His attorney alleged in June that the league assigned refs to work Game 6 of the 2002 Western Conference finals who would make calls ensuring the Los Angeles Lakers would beat Sacramento, extending the series to a seventh game and improving the TV ratings.
While saying it was "clearly not a well-refereed game," Pedowitz said it was called legally, and former Kings coach Rick Adelman agreed.
"I don't know who's evaluating calls or anything else. I said the same thing at the time and I'll say it today, the game was officiated differently in Games 6 and 7 than it was the first five. I said that at time and I believed that. That's not unusual," said Adelman, now coaching Houston. "I don't think they were manipulating anything. I don't think things were really perfect, either."
John Lauro, Donaghy's attorney, said the report goes to great lengths to "demonize" and "disparage" his client. For that reason, Donaghy "saw no reason to communicate with the Pedowitz group."
"If this had been an independent investigation we would have gladly cooperated," Lauro told ESPN.com's Mike Fish. "But we knew this was going to be a PR effort. ... It is a way that David Stern can say, 'I put nice little ribbon on this whole case and the only person that has ever done anything incorrect is Tim Donaghy.' That really was the whole purpose of the report."
ESPN.com senior writer Mike Fish and The Associated Press contributed to this report.