Henceforth seasonal adjustment of data for official statistics will be based on software JDemetra+


With an aim to improve quality of the seasonally adjusted data in official statistics from now on Central Statistical Bureau (CSB) will use software JDemetra+.

Within 2016, CSB will gradually move from seasonal adjustment software Demetra+ to new software JDemetra+. As compared to Demetra+, improvements of the software JDemetra+ include better data modelling and enhanced seasonality tests. With the help of JDemetra+ CSB will be able to provide data users with seasonally adjusted data of a higher quality.

When moving to the software JDemetra+, CSB is not changing time series seasonal adjustment methodology used till now. Still the TRAMO/SEATS method for data adjustments and calendar of national holidays in Latvia will be used, moreover, as new data are added to time series, the whole seasonally adjusted time series will be recalculated.  However, introduction of the new software does not change the explanation of the term "seasonally adjusted data" – data eliminating seasonal fluctuations and calendar effects.

In Latvia seasonal adjustment of official statistics is performed in line with the seasonal adjustment guidelines of the European Statistical System. Starting from 2 February 2015, Statistical Office of the European Union (Eurostat) and European Central Bank (ECB) are recommending software JDemetra+ as the official seasonal adjustment tool used within the European Statistical System, since functionality thereof allows better fulfilment of the seasonal adjustment requirements stipulated by the guidelines.

Eurostat and ECB report and recommendation for JDemetra+: http://ec.europa.eu/eurostat/cros/sites/crosportal/files/Jdemetra%2B%20release.pdf

European Statistical System guidelines on seasonal adjustment: http://ec.europa.eu/eurostat/cros/content/guidelines-sa-2015-edition

More information on software JDemetra+: http://ec.europa.eu/eurostat/cros/content/jdemetra-seasonal-adjustment-software_en

More information on TRAMO/SEATS method: http://www.sa-elearning.eu/tramoseats


Media requests:
Beate Danusēviča, Kristīne Romanovska
Information and Communication Section
media [at] csb [dot] gov [dot] lv
Tel.: + 37167366924, + 37167366621, + 37127880666


More information on changes in methodology:
Alīna Sadovska
Mathematical Support Division
E-mail: Alina [dot] Sadovska [at] csb [dot] gov [dot] lv
Tel.: + 371 67366618