The ZEW Index comes from the Mannheim Center for European Economic Research (ZEW), which collects economic expectations in Germany on a monthly basis. Up to 350 financial analysts take part in the survey. This creates an early indicator for future economic development that is valid for six months.
The ZEW index reflects the difference between positive and negative assessments. For example, if the respondents 40% think the economy will improve, but 50% think they will get worse, the index is -10. The proportion of those who do not expect any change in the economy does not play a role in the survey.