At the Federal Reserve's symposium late last week, central bankers from around the world and economists clashed over the best way to keep asset-price bubbles from developing. Some said regulatory tools are the most efficient way to deflate a boom without hindering the economy. Others said such tools are "unproven" and might shift central bankers' focus away from adjusting interest rates properly. The debate is an example of challenges faced by central bankers. Participants also said the global economic recovery might be uneven, but it likely will remain on track. While optimism reigned, some officials were struck by pessimism about the U.S. economic recovery.