Several surveys of consumer confidence and sentiment exist. The three best known and most respected are the Conference Board's Consumer Confidence Index, the University of Michigan's Index of Consumer Sentiment, and the Bloomberg Consumer Comfort Index. The Conference Board's Consumer Confidence Index is generally released on the last Tuesday of each month, while the University of Michigan survey usually issues its consumer sentiment index on the second to last Friday, followed by the revised final estimate two weeks later. The Bloomberg Consumer Comfort Index is released every Thursday, and contains information gathered for the week ended the previous Sunday. One way economists use the sets of consumer sentiment indexes to predict changes in economic variables is to chart the spread, or difference, between the Conference Board's Expectations and Present Situation Indexes. The stock market is also a notable influence on consumer attitudes and should be considered to evaluate the household sector and spending.