“…Institutional economics categorizes these structures as formal (rules, laws, constitutions) and informal (norms of behavior, conventions, and self-imposed codes of conduct) institutions. Griffith, Lee, and Yalcinkaya (2022) argue that its introduction into the GTCR is appropriate, as both theories make the same basic assumption—that is, firms within a country are profit maximizers and are willing to take advantage of opportunities afforded by the environment. To isolate the association between changes in ad spend by media channels and changes in retail format sales, we follow Griffith, Lee, and Yalcinkaya, who employ Davis and North's (1970, p. 133) definition of the institutional environment as “a set of fundamental political, social, and legal ground rules that govern economic and political activity.” We briefly discuss each of these elements, beginning with two elements of the formal institutional environment (i.e., political and regulatory institutions) and then the informal institutional environment (i.e., social institution).…”