“…This work adopts an ex post perspective in an effort to determine what effect trade liberalization has had on economic variables, such as productivity (Harrison, 1994, Tybout andWestbrook, 1995, Bernard andJensen, 1999), wages and employment (Beaulieu, 2000, Gaston andTrefler, 1997), plant production levels (Head and Ries, 1999), and the trade off between short run adjustment costs and long run efficiency gains (Trefler, 2001). In general, these studies have found that the costs and benefits associated with trade liberalization are both difficult to isolate, and unlikely to be substantial.…”