New evidence on modeling the Phillips Curve and time-varying volatility

This study re-examines the expectations augmented Phillips Curve allowing for time-varying volatility investigated by Ewing and Seyfried (2003) over a longer time period. Though there is evidence of time-varying variance associated with inflation, the inclusion of the conditional volatility in the mean equation of the GARCH-in-Mean specification of the Phillips Curve did not indicate a significant connection between higher levels of inflation attributable to volatility as found by Ewing and Seyfried (2003).