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