Intervention Specification Window
Use the Intervention Specification window to specify intervention effects to model the impact on the series of unusual events. Access it from the Intervention for Series window. For more information, see the section Interventions.
Controls and Fields
- Series
is the name and variable label of the current series.
- Label
is a descriptive label for the intervention effect that you specify. You can type a label in this field or allow the system to provide the label. If you leave the label blank, a label is generated automatically based on the options you specify.
- Date
is the date that the intervention occurs. You can type a date value in this field, or you can set the date by selecting a row of the data table on the right side of the window.
- Type of Intervention
- Point
specifies that the intervention variable is zero except for the specified date.
- Step
specifies that the intervention variable is zero before the specified date and a constant 1.0 after the date.
- Ramp
specifies that the intervention variable is an increasing linear function of time after the date of the intervention and zero before the intervention date.
- Number of lags
specifies the numerator order for the transfer function model for the intervention effect. Select a value from the pop-up list.
- Effect Decay Pattern
specifies the denominator order for the transfer function model for the intervention effect. The value "Exp" specifies a single lag denominator factor; the value "Wave" specifies a two-lag denominator factor.
- OK
closes the window and adds the intervention effect specified to the series interventions list.
- Cancel
closes the window without adding the intervention. Any options you specified are lost.
- Reset
resets all options to their initial values upon entry to the window. This might be useful when editing an intervention specification; otherwise, Reset has the same function as Clear.
- Clear
resets all options to their default values.
