  This paper studies the unconditional effects of a general policy
intervention, which includes location-scale shifts and simultaneous shifts as
special cases. The location-scale shift is intended to study a counterfactual
policy aimed at changing not only the mean or location of a covariate but also
its dispersion or scale. The simultaneous shift refers to the situation where
shifts in two or more covariates take place simultaneously. For example, a
shift in one covariate is compensated at a certain rate by a shift in another
covariate. Not accounting for these possible scale or simultaneous shifts will
result in an incorrect assessment of the potential policy effects on an outcome
variable of interest. The unconditional policy parameters are estimated with
simple semiparametric estimators, for which asymptotic properties are studied.
Monte Carlo simulations are implemented to study their finite sample
performances. The proposed approach is applied to a Mincer equation to study
the effects of changing years of education on wages and to study the effect of
smoking during pregnancy on birth weight.
