The paper examines various tests for assessing whether a time series model requires a slope component. We first consider the simple t-test on the mean of first differences and show that it achieves high power against the alternative hypothesis of a stochastic nonstationary slope as well as...

Policy evaluation based on the estimation of dynamic stochastic general equilibrium models with aggregate macroeconomic time series rests on the assumption that a representative agent can be identified, whose behavioural parameters are independent of the policy rules. Building on earlier work by...