Review of Economics and Statistics
Modelling the Coherence in Short-Run Nominal Exchange Rates: A Multivariate Generalized Arch Model [статья]
Опубликовано на портале: 01-07-2004Tim Bollerslev Review of Economics and Statistics. 1990. Vol. 72. No. 3. P. 498-506.
A multivariate time series model with time varying conditional variances and covariances but with constant conditional correlations is proposed. In a multivariate regression framework, the model is readily interpreted as an extension of the seemingly unrelated regression (SUR) model allowing for heteroskedasticity. Each of the conditional variances are parameterized as a univariate generalized autoregressive conditional heteroskedastic (GARCH) process. The descriptive validity of the model is illustrated for a set of 5 nominal European-US dollar exchange rates following the inception of the European Monetary System (EMS). EMS results are compared to estimates obtained for the same model using data over the pre-EMS period, July 1973 to March 1979. When compared to the pre-EMS free float period, the comovements between the currencies are found to be significantly higher over the later period.
Опубликовано на портале: 07-04-2004Hashem Dezhbakhsh Review of Economics and Statistics. 1990. Vol. 72. No. 1. P. 126-132.
A survey of several economic journals reveals that very often the Durbin-Watson and the portmanteau (Box-Pierce or Ljung-Box) tests are inappropriately applied to linear models with lagged dependent variables and exogenous regressors. Sampling experiments indicate that the Durbin-Watson performs poorly in models with more than one lag of the dependent variable, a situation commonly considered in the literature. The experiments also indicate that the portmanteau test is inadequate when applied to dynamic linear models with exogenous regressors. In addition, the performance of Durbin's h and m tests in models commonly used in the literature but not considered by previous studies is evaluated. The results reveal that among the four tests examined, the one which is the least frequently used in practice (the m test) has the best performance.