This month's report is due December 21. The housing slump may drag the index even lower.

What it is: A monthly snapshot that captures how consumers feel about the current state of the economy. The Consumer Sentiment Index is often compared with the Consumer Confidence Index, but the latter includes more information linked to the labor market.

History: In 1946, the Federal Reserve asked the University of Michigan to measure public confidence in the postwar economy. Today, researchers poll consumers and translate their answers into an index number—the higher, the better. Under President Bush, the index has averaged 89.4, compared with 97.8 under President Clinton.

Why it's important: Retailers use the index to forecast sales performance; economists use it to predict consumption; traders of fixed-income securities watch it because spending can affect interest rates. Although the index dipped in 2007, the year's mean is 88.3. (The average since 1960 is 88.1.)

The method: About 50 interviewers in a Michigan call center phone 500 randomly selected homes nationwide. The index is so up-to-date that on December 20, researchers will still be compiling data for the electronic release to subscribers the next day.

How to get it: In January 2007, the University of Michigan struck a deal with Reuters, granting the news service the right to distribute the monthly data along with a detailed analysis. While rates vary, subscribers can expect to pay about $4,800 a year. Nonsubscribers must settle for a one-page summary.

What's asked: Interviewers pose broad questions like "Do you think now is a good time or a bad time to buy a house?" and ask for estimates of such metrics as how much prices will rise or fall in the coming months.

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