Double exponential smoothing
= Double exponential smoothing
Double exponential smoothing supplements a smoothed level with a smoothed slope so that forecasts can extrapolate a local linear trend. Two common versions are <Holt's linear trend method>, with separate level and slope gains, and <Brown's double exponential smoothing>, which applies the same smoothing gain twice. They are different algorithms, not two names for one recursion. Neither version by itself models seasonal variation.