The anticipation of economic susceptible (early warning system) is urgent in predict the movement of a country's economy in the future. Leading Economic Index (LEI) or a precursor of economic indicators is a composite index that contains some specific economic variables to forecast economic activity and the movement of the composite index cycle precedes a country's business cycle movements. The process of formation LEI and business cycles do with seasonal adjustment (separate the seasonal component from its cyclical component) and detrending (separate the trend component from its cyclical component). Seasonal adjustment process using Census X-12 ARIMA. Detrending process using two filtration methods that will be compared to the band pass fi...