You know it's an election year when the government takes a one-month blip in an admittedly experimental economic index and spins it into a full-blown prediction for economic growth. The indicator in question is the new Transportation Services Index (TSI), launched earlier this year to measure transportation output.

There's no dispute that the index is on the rise. Transportation Secretary Norman Y. Mineta recently announced that the TSI increased by 1 percent from November to December 2003, to reach what the DOT somewhat breathlessly termed a historic high of 118.5. TSI tracks changes from 1996, meaning that transportation services in December rose 18.5 percent from 1996 levels. December's increase was the fourth consecutive increase in the new monthly index.

But the DOT wasn't content simply to deliver the welcome news. The agency went on to proclaim that "the new monthly measure [is] assumed to serve as a leading indicator of future growth for the economy." So as to leave no doubt as to the assumptions his agency was making, Mineta declared, "Today's results give us a clear indication of how much the strength of the transportation sector mirrors the strength of our economy. If you look at the data, every time the TSI heats up, the economy follows." A word of caution may be in order, however. A somewhat less giddy account of the index's rise elsewhere on the DOT Web site warns: "The TSI is still under development and is therefore considered experimental. It is being examined for refinements in data sources, methodologies and interpretations."

For the record, the Transportation Services Index is a new monthly economic indicator intended to measure the performance of the economy as reflected in the movement of freight and passengers. The freight measure increased 2.9 percent from November to December 2003 to reach a record high of 120.2. The passenger measure, however, decreased 3.6 percent from November to December 2003 to 114.4, after seven consecutive months of increases.