ey divided empirical studies of vertical restraints into two categories: studies of those that were voluntarily adopted and of those that were mandated or prohibited by the government. This survey found that of the twelve published studies of vertical restraints that were voluntarily adopted, nine found that the vertical restraint under study enhanced consumer welfare, whereas only N. Pac. Ry., 356 U.S. at 6-7; Jefferson Parish, 466 U.S. at 11-12. 42 Monsanto Co. V. Spray-Rite Serv. Corp., 465 U.S. 752, 762-63 (1984); State Oil, 522 U.S. at 18. See, e.g., City of Vernon V. S. Cal. Edison Co., 955 F.2d 1361, 1365-67 (9th Cir. 1992); Ill. ex rel. Burris V. Panhandle E. Pipe Line Co., 935 F.2d 1469, 1481-82 (7th Cir. 1991); Byars, 609 F.2d at 862-63; cases collected in Areeda and Hovenkamp (2008c, pp. 253-58). See, e.g., Bus. Elecs. Corp. V Sharp Elecs. Corp., 485 U.S. 717 (1988); Spectrum Sports, 506 U.S. at 459; State Oil Co. V. Khan, 522 U.S. 3 (1997); Leegin Creative Leather Prods., Inc. V. PSKS, Inc., 127 S. Ct. 2705 (2007); Barry Wright Corp. V. ITT Grinnell Corp., 724 F.2d 227, 236-37 (1st Cir. 1983) (Breyer, J.). Networks in Telecommunications three found that the practices reduced consumer welfare. In contrast, among the eleven studies of vertical restraints that were either mandated or prohibited by the government, nine found a reduction in consumer welfare, with the welfare impact of the remaining two studies being ambiguous. Although these authors recognize that the small number of studies made it difficult to make definitive claims, they describe the evidentiary record as "quite striking," "surprisingly consistent," "compelling" in its support for the proposition that privately imposed vertical restraints benefit consumers or at least do not harm them. At the same time, "[w]hen the government intervenes and forces firms to adopt (or discontinue the use of) vertical restraints, in contrast, it tends to make consumers worse off." The survey concluded that the empirical record thus provides "consistent and