OccBin: A Toolkit for Solving Dynamic Models With Occasionally Binding Constraints Easily

We describe how to adapt a first-order perturbation approach and apply it in a piecewise fashion to handle occasionally binding constraints in dynamic models. Our examples include a real business cycle model with a constraint on the level of investment, a New Keynesian model subject to the zero lower bound on nominal interest rates, and a model of optimal consumption choice in the presence of liquidity constraints. In each case, we compare the piecewise linear perturbation solution with a high-quality numerical solution that can be taken to be virtually exact. The piecewise linear perturbation method can adequately capture key properties of the models we consider. A key advantage of this method is its applicability to models with a large number of state variables.