Seasonal Multiplicative Smoothing

Crystal Ball uses the following initialization equation for this method:

Initialization formula for seasonal additive smoothing forecasting method.

Set Lt = P, St = Yt/P for t = 1 to s

Crystal Ball uses the following equations to calculate this method:

Formula for seasonal multiplicative smoothing

where the parameters are:

α—Alpha

γ—Gamma

m—Number of periods ahead to forecast

s—Length of seasonality

Lt—Level of the series at time t

St—Seasonal component at time t

Note:

First fit is available from period (s + 1)