Setting Holt-Winters method parameters

The Holt-Winters method allows for a weighted exponential smoothing that takes seasonality into account.

1. Open a forecast in the Model editor.
2. Click Add.
   The Forecast model selection page of the Add Model wizard opens.
3. Click Holt-Winters method and then click Next.
   The Holt-Winters method page of the Add Model wizard opens.
4. Select the frequency at which you expect to see seasonal effects on the data from the Seasonal frequency drop-down list.
5. Specify a value in the Smoothing constant (alpha) field.
   The number must be between zero and one. High values give recent periods more weight and low values give more weight to past data.
6. Specify a value in the Seasonal constant (beta) field.
   The number must be between zero and one. High values give recent periods more weight and low values give more weight to past data.
7. Specify a value in the Trend constant (gamma) field.
   The number must be between zero and one.
8. Click Finish.
   The Add Model wizard closes and the forecast model is displayed in the table.