The importance of common cyclical features in VAR analysis: a Monte-Carlo study

Despite the commonly held belief that aggregate data display short-run comovement, there has been little discussion about the econometric consequences of this feature of the data. We use exhaustive Monte-Carlo simulations to investigate the importance of restrictions implied by common-cyclical features for estimates and forecasts based on vector autoregressive models. First, we show that the ìbestî empirical model developed without common cycle restrictions need not nest the ìbestî model developed with those restrictions. This is due to possible differences in the lag-lengths chosen by model selection criteria for the two alternative models. Second, we show that the costs of ignoring common cyclical features in vector autoregressive modelling can be high, both in terms of forecast accuracy and efficient estimation of variance decomposition coefficients. Third, we find that the Hannan-Quinn criterion performs best among model selection criteria in simultaneously selecting the lag-length and rank of vector autoregressions.

The importance of Common-Cyclical Features in VAR analysis: a Monte-Carlo study (Preliminary Version)

Despite the belief, supported byrecentapplied research, thataggregate datadisplay short-run comovement, there has been little discussion about the econometric consequences ofthese data “features.” W e use exhaustive M onte-Carlo simulations toinvestigate theimportance ofrestrictions implied by common-cyclicalfeatures for estimates and forecasts based on vectorautoregressive and errorcorrection models. First, weshowthatthe“best” empiricalmodeldevelopedwithoutcommoncycles restrictions neednotnestthe“best” modeldevelopedwiththoserestrictions, duetothe use ofinformation criteria forchoosingthe lagorderofthe twoalternative models. Second, weshowthatthecosts ofignoringcommon-cyclicalfeatures inV A R analysis may be high in terms offorecastingaccuracy and e¢ciency ofestimates ofvariance decomposition coe¢cients. A lthough these costs are more pronounced when the lag orderofV A R modelsareknown, theyarealsonon-trivialwhenitis selectedusingthe conventionaltoolsavailabletoappliedresearchers. T hird, we…ndthatifthedatahave common-cyclicalfeatures andtheresearcherwants touseaninformationcriterium to selectthelaglength, theH annan-Q uinn criterium is themostappropriate, sincethe A kaike and theSchwarz criteriahave atendency toover- and under-predictthe lag lengthrespectivelyinoursimulations.

Testing for super-exogeneity in the presence of common deterministic shifts

This paper introduces the concept of common deterministic shifts (CDS). This concept is simple, intuitive and relates to the common structure of shifts or policy interventions. We propose a Reduced Rank technique to investigate the presence of CDS. The proposed testing procedure has standard asymptotics and good small-sample properties. We further link the concept of CDS to that of superexogeneity. It is shown that CDS tests can be constructed which allow to test for super-exogeneity. The Monte Carlo evidence indicates that the CDS test for super-exogeneity dominates testing procedures proposed in the literature.

Government actions to support coffee producers - an investigation of possible measures from the European Union

We outline possible actions to be adopted by the European Union to ensure a better share of total coffee revenues to producers in developing countries. The way to this translates, ultimately, in producers receiving a fair price for the commodity they supply, i.e., a market price that results from fair market conditions in the whole coffee producing chain. We plead for proposals to take place in the consuming countries, as market conditions in the consuming-countries side of the coffee producing chain are not fair; market failures and ingenious distortions are responsible for the enormous asymmetry of gains in the two sides. The first of three proposals for consumer government supported actions is to help in the creation of domestic trading companies for achieving higher export volumes. These tradings would be associated to roasters that, depending on the final product envisaged, could perform the roasting in the country and export the roasted – and sometimes ground – coffee, breaking the increasing importers-exporters verticalisation. Another measure would be the systematic provision of basic intelligence on the consuming markets. Statistics of the quantities sold according to mode of consumption, by broad “categories of coffee” and point of sale, could be produced for each country. They should be matched to the exports/imports data and complemented by (aggregate) country statistics on the roasting sector. This would extremely help producing countries design their own market and producing strategies. Finally, a fund, backed by a common EU tax on roasted coffee – created within the single market tax harmonisation programme, is suggested. This European Coffee Fund would have two main projects. Together with the ICO, it would launch an advertising campaign on coffee in general, aimed at counterbalancing the increasing “brandification” of coffee. Basic information on the characteristics of the plant and the drink would be passed, and the effort could be extended to the future Eastern European members of the Union, as a further assurance that EU processors would not have a too privileged access to these new markets. A quality label for every coffee sold in the Union could complement this initiative, helping to create a level playing field for products from outside the EU. A second project would consist in a careful diversification effort, to take place in selected producing countries.