Motivation: Our source, Instituto Nacional de Estatística (INE) of Portugal, reports house price indexes for total, new, and existing dwellings, but only in not seasonally adjusted (NSA) terms.

Response: For analytical convenience and international consistency, we have created seasonally adjusted (SA) counterpart series.

Properties: The series are indexed to 2015=100. Series start at either 1988Q1 or 2009Q1. Expect our SA series to be revised with each update. Supplemental series of this kind are marked in their source metadata with a secondary citation of "Moody's Analytics Adjusted."

The series reside in the historical catalog (Portugal » Real estate » Residential » Prices » Quarterly) and are:

• HPITAQ.IPRT = Real estate: House price index - All dwellings, (Index 2015=100, SA)
• HPINAQ.IPRT = New dwellings
• HPIXAQ.IPRT = Existing dwellings

Method:

1. Independently adjust the reported series using the U.S. Census Bureau's X-13 ARIMA program.
2. Extend HPITAQ.IPRT over the interval (1988Q1 to 2008Q4) using the growth rate of OECD series OCPIHPIAQ.IPRT.