Spillover Effects of Grocery Bag Legislation: Evidence of Bag Bans and Bag Fees

Abstract

We investigate the unintended consequences of carryout grocery bag (CGB) regulations by looking at the impact on sales of alternative plastic bag products. We extend the literature by studying two types of CGB regulations, bag bans and bag fees. Using retail scanner data and employing a general synthetic control method, we find that both types of CGB regulations are associated with significantly higher plastic trash bag sales. We estimate that CGB regulations lead to an average increase in purchased plastics of 127 pounds per store per month, ranging from 30 to 135 (37–224) pounds for 4-gallon (8-gallon) trash bags. These results confirm previous findings on bag bans and provide new evidence on bag fees. In general, the effects do not differ across CGB regulations, but some heterogeneity exists. Our results highlight unintentional spillover effects of narrowly targeted policies on other unregulated waste.

Appendices

Appendices

Detailed estimation results and the policy effect on unit prices of trash bags are presented in this section.

1.1 Appendix A: Endogeneity Checks and Estimation Results

See Figs.

Fig. 7

Policy effect on 4 and 8 gallon trash bag unit prices. Note The figures depict differences in trash bag sales between a treated county and synthetic control over time. The x-axis is a rescaled time horizon (in months), where Month 0 is the month implementing the policy. The policy effects on trash bag sales are estimated by Eq. (1). The intervals in gray indicate 95% confidence intervals constructed by bootstrapped standard errors. The result shows that the sales of 4 gallon trash bags increase in each study area due to the implementation of the CGB regulations

7 and

Fig. 8

Policy effect on 13 and above 13 gallon trash bag unit prices. Note The figures depict differences in trash bag sales between a treated county and synthetic control over time. The x-axis is a rescaled time horizon (in months), where Month 0 is the month implementing the policy. The policy effects on trash bag sales are estimated by Eq. (1). The intervals in gray indicate 95% confidence intervals constructed by bootstrapped standard errors. The result shows that the sales of 13 gallon trash bags are not significantly affected by the implementation of the CGB regulations

8 and Tables

Table 3 Effect of the CGB regulations on 4 and 8 gallon trash bag sales

3,

Table 4 Effect of the CGB regulations on 13 and 13+ gallon trash bag sales

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Table 5 Effect of the CGB regulations on 4 and 8 gallon trash bag unit prices

5 and

Table 6 Effect of the CGB regulations on 13 and 13+ gallon trash bag unit prices

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1.2 Appendix B: Synthetic Control Model Estimated with Less Observations

See Figs.

Fig. 9

Policy effect on 4 and 8 gallon trash bag sales (shorter period). Note The figures depict differences in trash bag sales between a treated county and synthetic control over time. The x-axis is a rescaled time horizon (in months), where Month 0 is the month implementing the policy. The policy effects on trash bag sales are estimated by Eq. (1). The intervals in gray indicate 95% confidence intervals constructed by bootstrapped standard errors. The result shows that the sales of 4 and 8 gallon trash bags increase in each study area due to the implementation of the CGB regulations

9,

Fig. 10

Policy effect on 13 and above 13 gallon trash bag sales (shorter period). Note The figures depict differences in trash bag sales between a treated county and synthetic control over time. The x-axis is a rescaled time horizon (in months), where Month 0 is the month implementing the policy. The policy effects on trash bag sales are estimated by Eq. (1). The intervals in gray indicate 95% confidence intervals constructed by bootstrapped standard errors. The result shows that the sales of 13 and above 13 gallon trash bags are not significantly affected by the implementation of the CGB regulations

10,

Fig. 11

Policy effect on 4 and 8 gallon trash bag unit prices (shorter period). Note The figures depict differences in trash bag sales between a treated county and synthetic control over time. The x-axis is a rescaled time horizon (in months), where Month 0 is the month implementing the policy. The policy effects on trash bag sales are estimated by Eq. (1). The intervals in gray indicate 95% confidence intervals constructed by bootstrapped standard errors. The result shows that the sales of 4 gallon trash bags increase in each study area due to the implementation of the CGB regulations

11,

Fig. 12

Policy effect on 13 and above 13 gallon trash bag unit prices (shorter period). Note The figures depict differences in trash bag sales between a treated county and synthetic control over time. The x-axis is a rescaled time horizon (in months), where Month 0 is the month implementing the policy. The policy effects on trash bag sales are estimated by Eq. (1). The intervals in gray indicate 95% confidence intervals constructed by bootstrapped standard errors. The result shows that the sales of 13 gallon trash bags are not significantly affected by the implementation of the CGB regulations

12,

Fig. 13

Effect of the CGB regulations on trash bag sales (shorter period). Note The average policy effects on trash bag sales are estimated by Eq. (1). The length of error bars indicates a 95% confidence interval produced by bootstrapped standard errors with the and estimated by Eq. (1). The vertical axis indicates the average treatment effect on treated over time, measured in the log of bags sold per store. Percentage numbers indicate converted change rates of increasing sales calculated by $\left[exp({\delta }_{it})-1\right]\times 100$, where ${\delta }_{it}$ is the average treatment effect as denoted in Eq. (1)

13 and

Fig. 14

Test for price endogeneity (shorter period). Note The average policy effects on trash bag prices are estimated by Eq. (1) with unit prices as the dependent variable and sales as the independent variable. The length of error bars indicates a 95% confidence interval produced by bootstrapped standard errors. The result shows that the policy does not have a significant effect on trash bag prices for all types of trash bags in each study area

14 and Tables

Table 7 Effect of the CGB regulations on 4 and 8 gallon trash bag sales (shorter period)

7,

Table 8 Effect of the CGB regulations on 13 and 13+ gallon trash bag sales (shorter period)

8,

Table 9 Effect of the CGB regulations on 4 and 8 gallon trash bag unit prices (shorter period)

9 and

Table 10 Effect of the CGB regulations on 13 and 13+ gallon trash bag unit prices (shorter period)

10.