The indicator approach was originated in the mid-1930s by economists at the United States’ National Bureau of Economic Research. Their research explored cyclical patterns of economic fluctuations that consist of expansions (periods of positive growth in general economic activity) followed by recessions (contractions in economic activity), which then merge into the expansion phase of the next cycle. Leading indicators are series that tend to shift direction in advance of the business cycle; for this reason, they receive the lion’s share of attention. Coincident indicators, such as employment and production, are broad series that measure aggregate economic activity; thus, they define the business cycle. Since no single time series fully qualifies as an ideal cyclical indicator, it is important to analyze groups of indicators and to look for consistent or common patterns. The leading and coincident economic composite indexes are useful summary measures of the cyclical indicators because, as averages, they tend to smooth out much of the volatility of individual series. A coincident economic index usually turns at the same time as the general economy. It also rises and falls at about the same pace as the gross domestic product (GDP). A leading economic index typically declines before recessions, yet sometimes gives a false signal, usually associated with major growth slowdowns that don’t turn into full blown recessions.