“…New features that have been introduced into these models generate nonlinearities that cannot be handled satisfactorily by standard perturbation solutions. 2 Examples include models with rare disasters (Fernández-Villaverde and Levintal, 2017), models with crisis equilibria that occur far from the steady state (Brunnermeier and Sannikov, 2014;Boissay et al, 2016), models with occasionally binding constraints 3 (Guerrieri and Iacoviello, 2015) and others. A common alternative to perturbation is projection (Judd, 1992), which is highly flexible and accurate.…”