The problem with productivity and how to parse it out

Washington

PRODUCTIVITY is probably the most important measure of economic health that policy makers know the least about.

Its pace will help determine how soon Federal Reserve Chair Janet Yellen and her colleagues increase interest rates and how far rates ultimately will rise. A quicker advance would argue for a later lift-off because the economy would have more room to run before bumping up against capacity constraints. It also eventually would require a higher ending point to prevent the more-vibrant expansion from overheating. Slower productivity would call for the opposite strategy.