Centre for Vocational Education Research LSE RSS Email Facebook Twitter


CEP discussion paper
Second-Order Approximation of Dynamic Models with Time-Varying Risk
Gianluca Benigno, Pierpaolo Benigno and Salvatore Nisticò
December 2010
Paper No' CEPDP1033:
Full Paper (pdf)

JEL Classification: C63

Tags: stochastic volatility; second order approximation

This paper provides first and second-order approximation methods for the solution of nonlinear dynamic stochastic models in which the exogenous state variables follow conditionally-linear stochastic processes displaying time-varying risk. The first-order approximation is consistent with a conditionally-linear model in which risk is still timevarying but has no distinct role - separated from the primitive stochastic disturbances - in influencing the endogenous variables. The second-order approximation of the solution, instead, is sufficient to get this role. Moreover, risk premia, evaluated using only a first-order approximation of the solution, will be also time varying.