NEW YORK     - March 15, 2010 - Consumer Metrics Institute constructs a U.S. consumption index based on actual transactions data for a range of major discretionary purchases such as cars, houses, durable goods, and vacations.

The advantage of the institute's method is that consumer transactions data might be able to indicate the direction of the economy before U.S. gross domestic product data is officially released.

The Daily Growth Index has led changes in the U.S. GDP reasonably well, at least going back to 2006. Admittedly, this is a short time frame.

Yet if their transactions data is a dependable leading indicator, then we could be in for a tumble.

That's because the Daily Growth Index just crashed, which means that U.S. GDP growth could be about to slump as well. Still, keep in mind that many economists expect about 3% U.S. GDP growth in 2010, so it wouldn't be a huge surprise if U.S. GDP growth slumped a little bit in the coming quarters.