The article estimates different monetary policy rules with trend inflation using US data after WWII. It shows that there are changes in the rules and inflation targets over time. The inflation gap persistence decreases during the Great Moderation period. The estimated parameters and regimes are consistent across various models. A test is proposed to check the consistency of the estimated rules. The results suggest that the stochastic autoregressive process is the most suitable model for trend inflation, especially after 1985.