Gallup’s US Economic Confidence Index is the average of two components: how Americans rate current economic conditions, and whether they feel the economy is improving or getting worse. The index has a theoretical maximum of +100 if all Americans say the economy is doing well and improving, and a theoretical minimum of -100 if all Americans say the economy is doing poorly and getting worse.
If you look at the chart above, rapid swings are not too common and happen, on average, every two years. In the last 10 years, it went down three times by a large number, and then recovered within half-a-year. After the recovery, it maintained its level for a few years.
Once, it went up by a lot and declined all within a year. So, it doesn’t seem that this Economic Confidence Index has long-term predictive power.