The impulse responses suggest that the key drivers of inflation in the short-term are
movements in the nominal effective exchange rate, whereas over the medium-term (a two- to
ten-quarter horizon) GDP growth and growth in credit to the economy are the principal
factors driving inflation. The response of inflation to a rise in the nominal interest rate
appears to be significant only in the first two quarters, and is—counter-intuitively—positive.
Castelnuovo and Surico (2006) suggest that this could arise if there is high persistence of
expected inflation and the central bank is passive rather than forward-looking in responding
to inflation, which together can generate multiple equilibria. They show that the omission in
the VARs of a variable capturing the high persistence of expected inflation under
indeterminacy can account for the ‘price puzzle’.