Transcript P7.3.10.
Future research issues
Rosa Ruggeri Cannata – Eurostat
Third International Seminar on Early Warning and
Business Cycle Indicators
17 – 19 November 2010, Moscow
Tendency surveys and seasonal adjustment
Characteristics of tendency surveys
– Questions ask managers/householders to eliminate
seasonal effects
– Seasonal movements in tendency surveys time series are
not very pronounced
Open debate: seasonal adjustment or just smoothing?
Tendency Surveys terminology
Seasonal adjustment: different methods
tendency surveys time series are stationary
Their seasonality is additive
Seasonal adjustment methods based on a
decomposition in trend-cycle component and seasonal
component can create distortions
It is important to analyse the results of different seasonal
adjustment methods
Tendency Surveys terminology
Seasonal adjustment and revisions
European surveys are generally not revised
Advantage: data are stable and easier to integrate
econometric models
Disadvantage: seasonal adjustment not in line with the
seasonal adjustment of macroeconomic variables
Tendency Surveys terminology
Seasonal adjustment: balances or components
Tendency surveys are usually published as a balance of
“positive” minus “negative” assessment
Seasonal adjustment is applied to the balance series
The two series of “positive” and “negative” evolution are
however available
When the seasonal movements of the two components
differ significantly it could be advisable to seasonal
adjust separately the two component series and
compare the results of:
– first subtract and then seasonal adjust the balances
– First seasonal adjust the components and then produce
balances
Tendency Surveys terminology
Alternative quantification methods
Tendency surveys are usually published as a balance of
positive minus negative evolution
Several studies on alternative methods did not show any
particular advantage in alternative quantification
methods
Limit of balances: the weight of “unchanged” answer is
not taken no consideration; some information is lost
Dissemination issue: publication of balances plus the
“unchanged” time series in order to give the full
information to the final user
Tendency Surveys terminology