By: Nguyen Van Dung - VNP 16
Supervisor: Dr. Tu Van Binh
The study investigates the causal relationship between inflation and inflation uncertainty in Vietnam over the period 1995-2010 using the two-step procedure. Inflation uncertainty is modeled by both symmetric model (GARCH(1,1)) and asymmetric models (TARCH(1,1), PARCH(1,1), EGARCH(1,1)). The results indicate that there exists an asymmetric impact of inﬂation shocks on inflation uncertainty, implying that a positive inflation shock induces higher inﬂation uncertainty, while a negative inflation shock induces lower inﬂation uncertainty. Based on information criteria including AIC, SC, and HQ as well as diagnostic tests, AR(13)-EGARCH(1,1) is considered the best model to model inflation uncertainty. Then Granger causality tests are employed to test the causality between inflation and inflation uncertainty (estimated by the AR(13)-EGARCH(1,1) model). The results support that a rise in inflation significantly leads to more inflation uncertainty, which confirms the Friedman-Ball hypothesis; and increasing inflation uncertainty leads to more inflation, confirming the Cukierman-Meltzer hypothesis, which indicates an "opportunistic" State Bank of Vietnam. The policy implication is that the monetary authorities have to keep inflation low, stable and predictable to eliminate the negative impact of inflation uncertainty.