X12ARIMASEATS

X12ARIMASEATS is a statistical software framework used for seasonal adjustment of economic time series, combining the X-12-ARIMA and SEATS approaches. It analyzes monthly or quarterly data to decompose a series into components: trend-cycle, seasonal, and irregular, and to produce a seasonally adjusted series.

The X-12-ARIMA component originated with the U.S. Census Bureau as an evolution of the X-11 family of seasonal adjustment methods. SEATS stands for Seasonal Extraction in ARIMA Time Series and was developed by European researchers to estimate the unobserved components from ARIMA models. The X12ARIMASEATS framework brings these strands together and underpins later standards such as X-13ARIMA-SEATS, which provides enhanced modeling, diagnostics, and automation.

Key features include optional transformation (for example Box-Cox), identification and adjustment for outliers, trading-day and Easter effects, ARIMA-based modeling, and the ability to produce diagnostic statistics and graphs. The package outputs include the original series, the seasonally adjusted series, the estimated seasonal component, the trend-cycle, and irregular component, along with accompanying metadata and revision history.

Usage: It is used by national statistical agencies and research institutions to produce and document seasonally adjusted measures of economy-wide indicators like GDP, industrial production, and consumer prices. While modern practices increasingly rely on X-13ARIMA-SEATS, X12ARIMASEATS remains a recognized framework for understanding seasonal adjustment methods and historical analyses.