The level of uncertainty will depend on several factors: the nature of the functional form used in the multivariate analysis; the type of econometric technique employed; the appropriateness of the statistical assumptions embedded in the model or technique; the comprehensiveness of the variables included in the analysis; and the accuracy of the data that are utilized. [...] Most studies on the impact of trade liberalization on the Canadian economy have focused only on the national impact, which belies the fact that Canada is composed of a distinct set of regional economies, whose ties to the North American and global economy are often quantitatively and qualitatively different. [...] The ability of regions to take advantage of trade liberalization and the nature of their trade with the rest of the world depends, at least in part, on their location relative to North American and world markets. [...] The ability of regions to take advantage of trade liberalization and the nature of their trade with the rest of the world depend, at least in part, on their location relative to North American and world markets. [...] It is the effect of tariffs on these structural characteristics that provided the foundation for early analyses of the potential consequences of free trade between Canada and the United States (Wonnacott and Wonnacott 1967) and proved to be one of the most important drivers of increases in welfare predicted to result from free trade (Harris 1984; Cox 1994).