This paper argues that typical applications of panel unit root tests should take possible nonstationarity in the volatility process of the innovations of the panel time series into account. Nonstationarity volatility arises for instance when there are structural breaks in the innovation...

Does immigration accelerate sectoral change towards high-productivity sectors? This paper uses the mass displacement of ethnic Germans from Eastern Europe to West Germany after World War II as a natural experiment to study this question. A simple two-sector specific factors model, in which...

What are the major barriers to services trade? To what extent would further liberalization of trade in services result in increased welfare gains and economic growth? It is critically important for governments to understand this if they are to participate effectively in, and maximize the...