Seasonal Additive Smoothing

Crystal Ball uses the following initialization equation for this method:

Initialization formula for seasonal additive smoothing forecasting method.

Set L_t = P, S_t = Y_t – P for t = 1 to s

Crystal Ball uses the following equations to calculate this method:

where the parameters are:

α—Alpha

γ—Gamma

m—Number of periods ahead to forecast

s—Length of seasonality

L_t—Level of the series at time t

S_t—Seasonal component at time t

Note:

First fit is available from period (s + 1)