Inflation, inflation uncertainty, and relative price dispersion: Evidence from bivariate GARCH-M models

One potential real effect of inflation is its influence on the dispersion of relative prices in the economy. Menu cost models generally imply that higher trend inflation will increase price dispersion. In contrast, signal extraction models predict that increased inflation uncertainty will raise relative price dispersion. Existing empirical studies do not distinguish between these separate hypotheses. We constuct a bivariate GARCH-M model of inflation and relative price dispersion to test these differing explanations in a single model and find that inflation uncertainty dominates trend inflation as a predictor of relative price dispersion.