A0629
Title: Common trends and long-run identification in nonlinear structural VARs
Authors: James Duffy - Oxford (United Kingdom) [presenting]
Sophocles Mavroeidis - Oxford University (United Kingdom)
Abstract: While it is widely recognised that linear (structural) VARs may omit important features of economic time series, the use of nonlinear SVARs has to date been almost entirely confined to the modelling of stationary time series because of a lack of understanding as to how common stochastic trends may be accommodated within nonlinear VAR models. This has, unfortunately, circumscribed the range of series to which such models can be applied and/or required that these series be first transformed to stationarity, a potential source of misspecification, and prevented the use of long-run identifying restrictions in these models. To address these problems, a flexible class of additively time-separable nonlinear SVARs is developed, which subsume models with threshold-type endogenous regime switching, both of the piecewise linear and smooth transition varieties. The Granger-Johansen representation theorem is extended to this class of models, obtaining conditions that specialize exactly to the usual ones when the model is linear. It is further shown that, as a corollary, these models are capable of supporting the same kinds of long-run identifying restrictions as are available in linear cointegrated SVARs.
