Social Explorer; Federal Housing Finance Agency House Price Index (HPI).
House Price Index Technical Documentation
27. For those HPIs that are seasonally adjusted, what approach is used in performing the seasonal adjustment?
The Census Bureau's X-12 ARIMA procedure is used, as implemented in the SAS software package. The automated ARIMA model-selection algorithm in X-12 is employed, which searches through a series of seasonality structures and selects the first that satisfies the Ljung-Box test for serial correlation.
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