(CNBC) The Federal Reserve wants to know what the internet is worth to you. The answer could help the central bank solve one of the most puzzling paradoxes of the modern economy: The current expansion is the longest in history yet productivity gains are weak and GDP growth while steady is far from stellar. In a speech this week Fed Chairman Jerome Powell raised the possibility that the problem is with the data itself. GDP measures the value of products and services that are bought and sold. But many of the greatest technological innovations of the internet age are free. Search engines e-mail GPS even Facebook the official economic statistics are not designed to capture the benefits they generate for businesses and consumers. Good decisions require good data but the data in hand are seldom as good as we would like" Powell said.