A large body of empirical research indicates that countries with low policy-induced trade barriers tend to enjoy rapid growth, ceteris paribus. In contrast, alternative theoretical models suggest that the relationship between trade barriers and growth may be contingent on the level of development. Employing a direct trade-barrier measure—ad valorem tariff rates—we find evidence of such a contingency: the marginal effect of tariffs on growth is declining in the level of per capita income. Moreover, evidence of a negative relationship between tariffs and growth is apparent only among the world's rich countries.

We show that state non-separable preferences à la Epstein–Zin–Weil (EZW) provide a tractable and flexible framework to study the economics of health and longevity. This utility representation: (1) admits a preference for timing of resolution of uncertainty regarding mortality risks; (2) links the marginal valuation of survival to the level of survival; (3) can preserve homotheticity even for low degrees of intertemporal substitution without generating implausible predictions regarding the value of life; and (4) adds needed flexibility to account for the empirical evidence on the value of life. We illustrate the implications of EZW preferences for the economic value of observed differences in life expectancy across countries and over time, and for the value of life over the life cycle.