A main component of customs unions is a common trade policy on imports from non-member countries. Trade policy covers both tariff and non-tariff barriers like trade procedures. We argue that since trade procedures vary markedly across EU countries, the EU is not, strictly speaking, a customs...

When analyzing panel data using regression models, it is often reasonable to allow for time-varying covariate effects. We propose a novel approach to modelling timevarying coefficients in panel data regressions, which is based on penalized regression techniques. To illustrate the usefulness of...