Abstract
Plastic bag regulations (PBRs) are widely adopted to reduce plastic pollution, yet empirical evidence on long-term consumer responses remains limited, particularly beyond California and short post-implementation periods. Prior studies have found that banned single-use grocery bags are often substituted with garbage bags. This study expands the temporal and geographic scope by examining the impact of PBRs on consumer expenditure for unregulated plastic disposal bags (PDB)—including waste bags, tall kitchen bags, trash bags, and lawn and leaf bags—using NielsenIQ retail scanner data from 2010 to 2020. In addition to the standard two-way fixed effects model, we employ the Callaway and Sant’Anna (2021) staggered difference-in-differences and synthetic difference-in-differences estimators to identify causal effects across product types. In a complementary analysis, we address a gap in the literature concerning household demand estimation for routine non-food goods. Using 2018 NielsenIQ Homescan data, we estimate a Heckman two-step sample selection model for household-level PDB purchases. Estimated own-price, income, and household-size elasticities suggest that demand is price inelastic and that PDB functions as a household necessity. Together, the two chapters provide extended empirical evidence on policy-induced substitution and provide new insights into the determinants of consumer demand for unregulated PDB.