In the last three decades, most of the existing literature using regression analysis to explore the effects of trade on development has conferred the first one a leading role in directly determining cross-country differences on income. Indeed, this should come at surprise, since what trade theory predicts and what results from General Equilibrium Models (an econometric-alternative quantitative tool) recently display are not completely aligned with conventional empirical evidence at hand. According to these sources, the effects of trade liberalization on welfare are indirect, transmitted through several channels, and dependent on multiple initial conditions. Much of such discrepancy may be due to measurement error and omitted variable problems, data limitations, and methodological shortcomings presented in regression analysis. On one hand, there is agreement over the fact that conventional proxies of trade openness contain severe measurement errors. In addition, data on control variables affecting well-being and believed to be correlated with trade became available just recently. On the other hand, and more importantly, the search for a possible contingent or conditional relationship between free trade and well-being has not been a priority in the agenda of mainstream literature with the exception of sporadic and isolated studies, despite the fact that trade theory has long recognized that possibility. Using newly developed policy-oriented measures of trade integration built with information from tariff rates, non-tariff-barriers, and subsidies, and controlling by multidimensional policy areas beyond those found in conventional literature, this study finds evidence of a contingent relationship between trade openness and well-being. More specifically, this investigation arrives at two conclusions. First, unilateral or one-way-street trade liberalization is not associated with higher levels of well-being, showing neither a direct impact nor a conditional one in the presence of complementary conditions. Second, gains in international market access, or multilateral trade openness, do not alone guarantee the achievement of higher levels of well-being, but do demonstrate significant potential for development in the presence of favorable internal conditions, such as those linked to business competitiveness and market efficiency, the promotion and respect of political rights among the citizenry, and the less concentrated distribution of economic and social opportunities.