Robust control allows policymakers to formulate policies that guard against model misspecification. The principal tools used to solve robust control problems are state-space methods [see Hansen, L.P., Sargent T.J., 2008. Robustness. Princeton University Press; Giordani, P., Söderlind, P., 2004....

The credibility problems of monetary policy are enlarged by transmission lags whenever the welfare criterion consists of arguments with differing transmission lags. If, as usually argued, prices react to monetary policy with a longer lag than output, the discretionary bias is substantially...