His comments during his appearance on CNN's "State of the Union," came after critics said that the board failed to interview key witnesses of last year's attack.
Although Pickering's report said there were failures and management problems at the State Department before the attack, some have said that the report did not go far enough.
"I've looked at it very carefully. I've listened to the hearings. A number of the criticisms were not based on the actual happenings," he said.
He also defended the board's questioning of former Secretary of State Hillary Clinton, which some have said was too lenient.
"She has already made clear the buck stopped with her," Pickering said. "But we were interested in where the decisions were made. And she did not make the security decisions."
Pickering also said that the board thoroughly investigated whether the four Americans who died in the attack could have been saved.
"Mike Mullen, who was part of this report and indeed worked very closely with all of us and shared many of the responsibilities directly with me, made it very clear that his view as a former chairman of the Joint Chiefs of Staff that there were nothing within range that could have made a difference," he said.