The most widely used statistical method in seasonal adjustment is
implemented in the X-11 Variant of the Census Method II Seasonal
Adjustment Program. Developed by the US Bureau of the Census, it
resulted in the X-11-ARIMA software and the X-12-ARIMA. While these
integrate parametric methods, they remain close to the initial X-11
method, and it is this "core" that Seasonal Adjustment with the X-11
Method focuses on. It will be an important reference for government
agencies, and other serious users of economic data.