Trend/Seasonal Models with First-Order Exponential Smoothing 

Use

Use the trend, seasonal, or seasonal trend model with first-order exponential smoothing for time series that have trend-like patterns and/or seasonal variations.

The following formula is used in forecast strategies 20, 21, 30, 31, 40 and 41, and in forecast strategies 50 to 56 where a trend, seasonal, or seasonal trend model is determined with first-order exponential smoothing. The calculation takes into account both trend and seasonal variations. The basic value, the trend value, and the seasonal index are calculated after the initial period.

For more information, see Model Initialization.

Formula for First-Order Exponential Smoothing in a Trend, Seasonal or Seasonal Trend Model

You can also use this formula with an additional phi parameter. For more information, see Trend Dampening with Phi Parameter.