Hodrick-Prescott Filter
The Hodrick-Prescott (HP) filter is a specialized filter for trend and business cycle estimation (no seasonal component). Suppose a time seriesytcan be additively decomposed into a trend and business cycle component. Denote the trend componentgtand the cycle componentct. Then
The HP filter finds a trend estimate, , by solving a penalized optimization problem. The smoothness of the trend estimate depends on the choice of penalty parameter. The cycle component, which is often of interest to business cycle analysts, is estimated as .
hpfilter
返回估计趋势和周期分量of a time series.