1. SA results obtained with Demetra2.2 and Demetra+
Faiz Alsuhail,
SA Workshop, 6th March

2. Background
The presentation is about the total (monthly) output of the economy.
The comparison is between results by Demetra 2.2 Demetra+ (.NET-version).
Tramo/Seats is used, model setting are the same in both Demetra 2.2 and Demetra+.
07/12/2018

3. Correction for Trading Day Effects 1 Regressor(s) (holiday-corr.)
Information on Models
Demetra 2.2
Demetra+
Series Span (n° of obs.)
Jan Sept2011 (189)
Jan Sept2011
Method
Tramo/Seats
Transformation
Logarithm
Mean Correction
None
Correction for Trading Day Effects
1 Regressor(s) (holiday-corr.)
Trading day value 1
0,0031
0,0039
Trad1 t-value
10,97
19,087
Trading day value 2
-0,0078
-0,0097
Trad2 t-value
-10,97
-19,087
Correction for Easter Effect
Correction for Outliers
2 Outlier
2 Outliers
LS Marr2008 t-value
-3.89
-4,163
LS Tamm2009 t-value
-3.73
-3,244
Specif. of the ARIMA model
(0 1 1)(0 1 1)
Non-seas. MA (lag 1) value
-0,463
Non-seas. MA (lag 1) t-value
[-1.972, 1.972] 5%
-6,973
Seasonal MA (lag 12) value
-0,589
Seasonal MA (lag 12) t-value
-9.99 [-1.972, 1.972] 5%
-8,414
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4. Seasonally adjusted time series, Total output of the economy, 1/2005-7/2011
Faiz Alsuhail
07/12/2018

5. Differences in SA growth rates (%-points)
07/12/2018

6. Questions to be considered
Should an NSI try to keep the old SA models when switching from Demetra 2.2 to Demetra+ ?
Yes, to be consistent with the past.
Partly (only for level shifts and trading day correction).
No, the results will be revised anyway.
How should the user be informed about the possible revisions?
How to justify the revisions?
Should NSI’s talk about change in software or method?
07/12/2018