Smoothing Model Specification Window
Use the Smoothing Model Specification window to specify and fit exponential
smoothing and Winters method models.
Access it from the Develop Models window using the Fit Model submenu of the Edit pull-down
or from the pop-up menu when you click an empty area of the model table.
Controls and Fields
- Series
-
is the name and variable label of the current series.
- Model
-
is a descriptive label for the model that you specify.
You can type a label in this field or allow the system to provide a label.
If you leave the label blank,
a label is generated automatically based on the options you specify.
- Smoothing Methods
-
- Simple Smoothing
-
specifies simple (single) exponential smoothing.
- Double (Brown) Smoothing
-
specifies double exponential smoothing
using Brown's one parameter model
(single exponential smoothing applied twice).
- Seasonal Smoothing
-
specifies seasonal exponential smoothing.
(This is like Winters method with the trend term omitted.)
- Linear (Holt) Smoothing
-
specifies exponential smoothing of both the series level and trend
(Holt's two parameter model).
- Damped-Trend Smoothing
-
specifies exponential smoothing of both the series level and trend
with a trend damping weight.
- Winters Method - Additive
-
specifies Winters method with additive seasonal factors.
- Winters Method - Multiplicative
-
specifies Winters method with multiplicative seasonal factors.
- Smoothing Weights
-
displays the values used for the smoothing weights.
By default, the Smoothing Weights fields are set to optimize,
which means that the system will compute the weight values
that best fit the data.
You can also type smoothing weight values in these fields.
- Level
-
is the smoothing weight used for the level of the series.
- Trend
-
is the smoothing weight used for the trend of the series.
- Damping
-
is the smoothing weight used by the damped-trend method
to damp the forecasted trend towards zero as the forecast
horizon increases.
- Season
-
is the smoothing weight used for the seasonal factors in
Winters method and seasonal exponential smoothing.
- Transformation
-
displays the series transformation specified for the model.
When a transformation is specified, the model is fit to the transformed
series, and forecasts are produced by applying the inverse transformation to
the model predictions.
Select Log, Logistic, Square Root, Box-Cox, or None
from the popup list.
- Bounds
-
displays the constraints imposed on the fitted smoothing weights.
Select one of the following from the popup list:
- Zero-One/Additive
-
sets the smoothing weight optimization region to the
the intersection of the
region bounded by the intervals from zero (0.001) to one (0.999)
and the additive invertible region. This is the default.
- Zero-One Boundaries
-
sets the smoothing weight optimization region to the
region bounded by the intervals from zero (0.001) to one (0.999).
- Additive Invertible
-
sets the smoothing weight optimization region to
the additive invertible region.
- Unrestricted
-
sets the smoothing weight optimization region to be unbounded.
- Custom
-
brings up the Smoothing Weights window
to enable you to customize the constraints for
smoothing weights optimization.
- OK
-
closes the Smoothing Model Specification window
and fits the model you specified.
- Cancel
-
closes the Smoothing Model Specification window without fitting the model.
Any options you specified are lost.
- Reset
-
resets all options to their initial values upon entry to the window.
This may be useful when editing an existing model specification;
otherwise, Reset has the same function as Clear.
- Clear
-
resets all options to their default values.
Copyright © 1999 by SAS Institute Inc., Cary, NC, USA. All rights reserved.
