 I'm David Brancaccio in New York. There's a new economic indicator in town. This one analyzes the U.S. economy in real time, and it's powered by artificial intelligence. Marketplace's Nancy Marshall-Genzer is here with some details. This new tool is called the Zeta Economic Index. The free index uses AI to track and analyze consumer behavior and then crunches that data to assess the state of the economy and try to predict economic trends.