X-12-ARIMA is the Census Bureau's new seasonal adjustment program. It belongs to the methodological lineage of the Census Bureau's X-11 program (Shiskin, 1967) and Statistics Canada's X-11-ARIMA and X-11-ARIMA/88 (Dagum, 1988) programs.  These methods estimate seasonality mainly by applying moving average filters to a possibly modified version of the input series. The modifications might include adjustments for extreme values, trading day effects, or holiday effects also estimated by the program. The filters are chosen from a fixed set of filters, partially or—in X-11-ARIMA/88 and X-12-ARIMA, possibly completely—automatically, on the basis of certain signal-to-noise ratios. See also U.S. Bureau of the Census (1998).