It's reduced the incidence of meritless cases, says Don Sensabaugh, counsel to the West Virginia Medical Association:

In particular, he said, the changes have decreased "shotgunning," in which a lawyer would sue any doctor who had seen his or her client.

"And then, as the case went on, they'd figure out who was responsible," Sensabaugh said. "It was not infrequent that at the end of discovery or before trial, two or three doctors would be dismissed [from the suit]. That was an unnecessary expense to the system."

(via KevinMD).