TY - JOUR AU - Judd,Kenneth AU - Maliar,Lilia AU - Maliar,Serguei TI - Numerically Stable Stochastic Simulation Approaches for Solving Dynamic Economic Models JF - National Bureau of Economic Research Working Paper Series VL - No. 15296 PY - 2009 Y2 - August 2009 UR - http://www.nber.org/papers/w15296 L1 - http://www.nber.org/papers/w15296.pdf N1 - Author contact info: Kenneth L. Judd Hoover Institution Stanford University Stanford, CA 94305-6010 Tel: 650/723-5866 Fax: 650/723-1687 E-Mail: kennethjudd@mac.com Lilia Maliar Office T-24 Hoover Institution Stanford University CA 94305-6010, USA Tel: 6507253416 Fax: 6507231687 E-Mail: maliarl@stanford.edu Serguei Maliar Office T-24 Hoover Institution Stanford University CA 94305-6010, USA Tel: 6507253416 Fax: 6507231687 E-Mail: maliars@stanford.edu AB - We develop numerically stable stochastic simulation approaches for solving dynamic economic models. We rely on standard simulation procedures to simultaneously compute an ergodic distribution of state variables, its support and the associated decision rules. We differ from existing methods, however, in how we use simulation data to approximate decision rules. Instead of the usual least-squares approximation methods, we examine a variety of alternatives, including the least-squares method using SVD, Tikhonov regularization, least-absolute deviation methods, principal components regression method, all of which are numerically stable and can handle ill-conditioned problems. These new methods enable us to compute high-order polynomial approximations without encountering numerical problems. Our approaches are especially well suitable for high-dimensional applications in which other methods are infeasible. ER -