Treasury Secretary Jacob J. Lew said the growth of the Chinese economy will depend on the pace and character of changes flagged by the ruling Communist Party earlier this week.

“I think there is going to continue to be progress, but the question is how much and how quickly,” Lew said in e-mailed comments sent after his meetings with Chinese officials in Beijing. “The direction is significant, but the character and the pace of change matters. The common focus between the U.S. and China is the importance of laying a foundation for future growth. It’s in both of our interests for both of us to succeed.”