But some said the loopholes raised questions about the effectiveness of sanctions.

But the incident raises questions about the effectiveness of the government plan to protect the White House from terrorists in planes.

But safety board officials said the crash had raised questions about the effectiveness of programs intended to catch unsafe bus companies.

Just after nightfall Wednesday, another raid raised questions about the effectiveness of American intelligence here.

This raises serious questions about the effectiveness of the discipline they created.

The officials added that the procedures raised serious questions about the effectiveness of recalls of medical equipment.

Officer Stewart's killing raised questions about the effectiveness of the bullet-resistant vest he wore.

"It is raising questions about the effectiveness of the police department's watchdog department," he said.

There have been questions raised about the effectiveness of the decontamination process, especially regarding the removal of caesium-137.

But what is clear is that serious questions have to be raised about the effectiveness of international controls over nuclear materials.