It was thought that a Vector Autoregressive (VAR) approach was suitable for looking at the
main drivers of inflation in Vietnam, primarily because this approach allows us to fully
capture the interaction among macroeconomic variables and their feedback effects. The
endogenous variables in the VAR included CPI inflation, GDP growth, growth in credit to
the economy, percentage change in the nominal effective exchange rate, and the nominal
interest rate. The VAR was estimated over the period 2004Q1 to 2012Q2. Exogenous
variables included the percentage change in the import price deflator as well as dummies for
structural break in 2007Q4 (to allow for shifts in the intercept term and in the coefficient on
the import price deflator). In light of the short time period involved a lag length of one was
chosen, consistent with the results of the Schwarz Information Criterion for optimal lag
length. The stability of the model was checked based on roots of the AR characteristic
polynomial and all roots were found to be inside the unit circle, indicating that the model
fulfills the stability condition.