In a broad view to the confidence to sentiment indices tend to capture the gauge to consumers' stance about the current and even future outlook for economic conditions in the economy.
There a number of indexes released in each economy that measure the sentiment, ones are dedicated for consumers and others for businesses. For that here are some of the highly accounted for indexes in from various economies:
Consumer Confidence Index (CCI) by the US Conference Board on a monthly basis
Michigan Consumer Sentiment Index (MCSI) very useful released in two reading the preliminary released around the 10th of each month and followed by the revised final on the first of the month for the prior month.
IFO Business Climate Index a monthly survey targeting firms in various fields such as manufacturing, construction, wholesaling, and retailing on current and expected business conditions.
General Effect
The importance of consumer confidence index at currency market is important, because it influences consumers' consumption levels, so if the expected percentage inclines, means that the consumer confidence in the domestic economy will likely to improved and it affects consumers' willingness to spend money that allows them to obtain available goods and services; as a result the aggregate demand will increase which cause rising production by different industries. Accordingly the effect is positive to the currencies.
At the same time this indicator has a similar effect on the stock market, because if it shows positive figures that mean it will leave a significant improvement on several companies stocks in different sectors, as the outcome to increasing consumers' spending means more demand, which pushes up stock indices.
Some studies proved that this effect might be theoretically true, that in fact it might not leave any considerable effect on the local currency; that's why the effect is not necessarily valid every time and is moderate.
Best Case Consumer confidence in the U.S. economy is projected to incline as the best case scenario would be if the reading comes in with higher readings which might increase spending in the economy and revive it from the prolonged recession it is facing since consumers tend to spend when they are confident with the state of their economy.
Worst Case The worst case scenario would be if consumer confidence showed a plunge from the prior reading as this would pare spending further in the economy since Americans tend to save at a time of crisis while already there are projections of an extended recession as third quarter the nation contracted by 0.5 percent.