The University of Michigan tracks consumer sentiment in the US based on surveys of a random sample of U.S. households and creates the US Index of Consumer Sentiment (ICS). This index is an attempt to measure consumer sentiments in personal finances, business conditions, and other topics. Most surveys, however, do not accurately reflect what consumers actually think. Because of this, many economists do not use this index to determine consumer sentiment and expectations. Why do you suppose that economists generally are more interested in the Index of Consumer Sentiment’s validity than they are in its reliability as a predictor?