"There are different pieces to that reason."
Some of it, he said, is on the Sixers providing better defensive execution. A lot of the problems occur when opponents drive to the middle of the lane and pass the ball out to wide-open three-point shooters.
Brown, however, took full responsibility for the defensive woes. And he's determined to improve in that area heading into the NBA all-star break.
Shooting a lot of three-pointers "is an evolution of the game," he said. "This is the way the game is headed, and you better jump on [being able to defend it.]
"I believe that by continuing to focus on these areas, we are going to improve. That's a judgment that sometimes will show up with stats, sometimes with gut feel. But we know that's a problem that needs to be addressed."
The Sixers surrendered 21 three-pointers in consecutive games against Portland and Brooklyn.
The Blazers made 21 of 37 three-pointers in a 139-105 win on Dec. 14 at the Wells Fargo Center. Two nights later, the Nets made 21 of 35 threes in a 130-94 blowout in Brooklyn.
"We have to take pride in guarding guys and keeping guys in front of us," power forward Thaddeus Young said. "We need to force [penetrating players] to the baseline. I think that's the biggest part. Not getting letting teams go middle on us. That's how they get kick-out threes."
The Sixers don't know when Arnett Moultrie, who injured his ankle before training camp, will participate in an all-out scrimmage. But he's preparing for it.
The reserve power forward, who had surgery on his left ankle in the preseason, resumed participating in team drills on Thursday as part of his rehab.
"He's run around and scripted," Brown said. "He couldn't do much physically as far as five-on-five and three-on-three.
"But he got up and down the floor. Endurance-wise, he did a good job."
"There's a bounce, an energy, an athleticism we would embrace with our current roster," Brown said. "I know he is excited to come back and play. And I know his teammates are excited to have him come back and play. It's been a long time coming."