“…Comparison of predesignation and postdesignation growth of the zone, as was done in the study by Jones and others (1985), may pro vide a better evaluation of program effects, but changes in zone growth could be due to more general economic forces, such as national booms or recessions, or changes in the overall national performance of specific industries. An even better approach is to compare changes in the growth of local areas targeted by an economic development program with changes in growth in control areas, as was done in the studies by Papke (1991), Luger and Goldstein (1990), Papke (1990), and Rubin and Wilder (1989). But choosing control areas which ideally would be iden tical in all observed and unobserved characteristics to the targeted local areas is difficult.…”