X11

X11 is a method of seasonal decomposition and adjustment. It decomposes the input variable into seasonal, trend-cycle and irregular components, and executes seasonal adjustment.

NOTE. In the X11 method, the input variable also serves as the output variable. To create an equation, set the variable binding to itself. The method is available only for monthly or quarterly frequency variables.
The method is supported only in Windows.

To set up method parameters, use the following side panel tabs:

Equation. It enables the user to change basic calculation options: applied seasonality model, applied adjustments, and so on.

Moving Average. Sets moving average calculation method for each element of the source series calendar frequency.

Weight Coefficients. It enables the user to set weight coefficients for week days.

Make sure that the side panel is displayed.
Select output variable or one of the equation links of the X11 type.
Go to the Equation side panel tab.

Method parameters:

Seasonal Effect. Specify the model to be applied to select the seasonal component of the input variable:

Additive. Default. The variable is considered as a sum of systematic and irregular components.
Multiplicative. The variable is considered as a product of systematic and irregular components.

Working Day Adjustment. If the checkbox is selected, the working day adjustment is used. Adjustment methods:

Always. Working day adjustment is applied.
Automatically. It is automatically determined whether working day adjustment should be applied.

NOTE. Working day adjustment is applied only for monthly data.

Holiday Adjustment. If the checkbox is selected, the holiday adjustment is used. The adjustment increases calculation accuracy. Adjustment methods:

Easter Only.
Easter, Labor Day, Thanksgiving Day
Use Fisher Criterion.

NOTE. The holiday adjustment is used only for the multiplicative seasonality model calculated on monthly data.

Sigma Limits. Most of the variables contain outliers. They can distort seasonality and trend estimations. The X11 method decreases the influence of outliers by excluding the values, which are not included to the specific range or by transforming these values.
The width of the range is set by lower and upper sigma limits in the Sigma Limits group of parameters. By default, the lower limit is 1.5, the upper limit is 2.5.

Sliding Spans. If the checkbox is selected, sliding spans are used in calculation. The checkbox is deselected by default.

Save to Variable. Specify data, which will be loaded to output variable:

Prior adjusted or source series (B1).
Seasonal Component (D1).
Seasonally adjusted series (D11).
Trend-cycle component (D12).
Irregular component (D13).

For details about loaded data, see theCensus1 article.