Nudging Away from Plastic Bags with Charitable Donations

Jerrod Penn, Sapana Bastola and Wuyang Hu

Article Figures & Data

  • Table 1 Descriptions of Variables
    VariableMeanStd. Dev.Description
    Disposable bag0.380.481 if customer used a plastic bag, 0 otherwise (dependent variable)
    Token0.850.361 if after implementation of token program, 0 otherwise
    StoreA0.700.461 if observation comes from the store A (treated convenience store), 0
    otherwise
    Total items2.091.44Total number of items purchased per transaction
    Small items1.291.19Number of small items purchased per transaction (can of soda or smaller)
    Medium items0.630.97Number of medium items purchased per transaction (any items in
    between small and large)
    Large items0.170.50Number of large items purchased per transaction (2 liters of soda, half-
    gallon of milk, 6-packs of bottled water)
    Evening0.620.491 if purchase occurred in evening (after 5 p.m.), 0 otherwise
    Weekday0.930.261 if the purchase occurred Monday through Friday, 0 otherwise
    Preceding customer0.380.481 if the previous customer used a plastic bag, 0 otherwise
    Female0.490.52Gender of the customer: 1 if female, 0 otherwise
    Percentage of plastic
    bag use
    0.440.13Percentage of the customer using plastic bags for each day before
    intervention
    Trend4.52.36Trend representing each day before the intervention of token program
    (since we had 8 control days, trend represented as 1, 2…,8)
  • Table 2 Results from Logit Model
    Dependent VariableCoefficientStd. Errorp-value
    Trend0.0040.0160.777
    Trend*StoreA0.0150.0130.262
    Constant0.3880.0710.000
    R-squared0.139
    • Note:The dependent variable is the daily percentage of customers using at least one plastic bag. Results are based on a robust ordinary least squares estimation.

  • Table 3 Summary of Survey Data
    CharacteristicTotal (n=436)Store A (n=282)Store B (n=154)p-value Testing Store A=B
    Gender0.719
    Female0.560.550.57
    Race0.728
    Black0.190.180.2
    White0.650.660.62
    University0.000
      status
    Freshman0.490.410.63
    Sophomore0.260.280.22
    Junior0.150.200.07
    Senior0.070.080.06
    Graduate0.020.020.01
    Staff0.010.010.01
    Living0.109
      location
    University0.820.800.86
      dorms
    Off-campus0.110.120.09
      <10 min.
      walk
    Off-campus0.060.070.05
      further
      away
    Frequency0.000
      of visiting
      store A
    Never0.140.050.29
    Rarely0.180.150.25
    Sometimes0.330.360.29
    Often0.350.440.17
    Frequency0.000
      of visiting
      store B
    Never0.330.480.06
    Rarely0.200.220.15
    Sometimes0.260.190.39
    Often0.210.110.40
  • Table 4 Comparison of Patrons to the Two Stores before and after Intervention
     Before InterventionAfter Intervention
    Characteristic (n=436)Total (n=148)Store A (n=96)Store B (n=52)p-value Store A=BTotal (n=288)Store A (n=186)Store B (n=102)p-value Store A=B
    Gender0.5960.955
      Female0.490.470.520.600.600.60
    Race0.9150.728
      Black0.180.190.150.190.170.22
      White0.620.620.650.660.690.60
    University status0.0440.001
      Freshman0.540.450.710.460.390.59
      Sophomore0.240.300.130.270.270.27
      Junior0.160.190.100.150.210.06
      Senior0.040.030.020.090.100.07
      Graduate0.010.020.000.020.020.01
      Staff0.010.010.020.010.010.00
    Living location0.5140.123
      University dorms0.860.840.880.800.770.85
      Off-campus0.080.080.080.130.140.10
        <10-min. walk
      Off-campus further0.050.060.040.070.080.05
        away
    Frequency of visiting
    store A
    <0.001<0.001
      Never0.110.030.270.150.060.30
      Rarely0.190.170.230.180.140.26
      Sometimes0.340.350.310.330.360.28
      Often0.360.450.190.340.440.16
    Frequency of visiting
    store B
    <0.001<0.001
      Never0.270.380.060.360.520.06
      Rarely0.210.250.150.190.210.15
      Sometimes0.340.240.520.220.170.32
      Often0.180.130.270.230.100.47
  •  Model IModel IIModel IIIModel III’
     CoefficientMarginal EffectCoefficientMarginal EffectCoefficientMarginal EffectCoefficientMarginal Effect
    Token0.044
    (0.212)
    0.006
    (0.031)
    0.021
    (0.235)
    0.003
    (0.030)
    0.248
    (0.295)
    0.035
    (0.042)
    0.273
    (0.229)
    0.039
    (0.032)
    storeA1.031***
    (0.335)
    0.148***
    (0.048)
    1.243***
    (0.376)
    0.160***
    (0.048)
    1.001***
    (0.340)
    0.143***
    (0.049)
    1.021***
    (0.334)
    0.147***
    (0.048)
    Token*StoreA–0.747***
    (0.258)
    –0.114***
    (0.041)
    –0.915***
    (0.279)
    –0.128***
    (0.042)
    –0.788***
    (0.260)
    –0.115***
    (0.043)
    –0.795***
    (0.259)
    –0.115***
    (0.058)
    Total items1.516***
    (0.052)
    0.218***
    (0.004)
    1.521***
    (0.053)
    0.218***
    (0.004)
    1.517***
    (0.053)
    0.218***
    (0.004)
    Small items1.310***
    (0.055)
    0.169***
    (0.005)
    Medium items2.054***
    (0.076)
    0.265***
    (0.006)
    Large items2.969***
    (0.146)
    0.383***
    (0.015)
    Evening0.281***
    (0.106)
    0.040***
    (0.015)
    0.275**
    (0.113)
    0.036**
    (0.015)
    0.325***
    (0.111)
    0.047***
    (0.016)
    0.280***
    (0.108)
    0.040***
    (0.015)
    Weekday–0.359*
    (0.184)
    –0.052*
    (0.026)
    –0.178
    (0.192)
    –0.023
    (0.025)
    –0.415**
    (0.189)
    –0.059**
    (0.027)
    –0.346*
    (0.185)
    –0.050*
    (0.026)
    Preceding customer0.184**
    (0.073)
    0.026**
    (0.011)
    0.165**
    (0.077)
    0.021**
    (0.010)
    0.166**
    (0.074)
    0.024**
    (0.011)
    0.174**
    (0.073)
    0.025**
    (0.011)
    Female0.174***
    (0.066)
    0.025***
    (0.009)
    0.127*
    (0.070)
    0.016*
    (0.009)
    0.176***
    (0.066)
    0.025***
    (0.009)
    0.172***
    (0.066)
    0.025***
    (0.009)
    Constant–4.960***
    (0.402)
    –5.316***
    (0.445)
    –5.023***
    (0.421)
    –4.986
    (0.406)
    Middle–0.393***
    (0.128)
    –0.056***
    (0.018)
    Token*Middle–0.257**
    (0.128)
    –0.037**
    (0.018)
    Token*End
    Observer FEYesYesYesYes
    Cashier FEYesYesYesYes
    Week FENoNoYesNo
    Pseudo R–squared0.3290.3880.3310.330
  •  Model III”Model IVModel IV’Model IV”
     CoefficientMarginal EffectCoefficientMarginal EffectCoefficientMarginal EffectCoefficientMarginal Effect
    Token0.273
    (0.229)
    0.039
    (0.033)
    0.231
    (0.335)
    0.030
    (0.043)
    0.236
    (0.252)
    0.030
    (0.032)
    0.236
    (0.252)
    0.030
    (0.032)
    StoreA1.021***
    (0.334)
    0.147***
    (0.048)
    1.223***
    (0.378)
    0.157***
    (0.049)
    1.233***
    (0.375)
    0.159***
    (0.048)
    1.233***
    (0.375)
    0.159***
    (0.048)
    Token*StoreA–0.795***
    (0.259)
    –0.115***
    (0.040)
    –0.963***
    (0.281)
    –0.129***
    (0.045)
    –0.960***
    (0.280)
    –0.128***
    (0.042)
    –0.960***
    (0.280)
    –0.128***
    (0.042)
    Total items1.517***
    (0.053)
    0.218***
    (0.004)
    Small items1.313***
    (0.056)
    0.169***
    (0.005)
    1.310***
    (0.055)
    0.169***
    (0.005)
    1.310***
    (0.055)
    0.169***
    (0.005)
    Medium items2.059***
    (0.076)
    0.265***
    (0.006)
    2.056***
    (0.076)
    0.265***
    (0.006)
    2.056***
    (0.076)
    0.265***
    (0.006)
    Large items2.966***
    (0.147)
    0.381***
    (0.015)
    2.966***
    (0.146)
    0.382***
    (0.015)
    2.966***
    (2.966)
    0.382***
    (0.015)
    Evening0.280***
    (0.108)
    0.040***
    (0.015)
    0.316***
    (0.119)
    0.041***
    (0.015)
    0.269**
    (0.114)
    0.035**
    (0.015)
    0.269**
    (0.114)
    0.035**
    (0.015)
    Weekday–0.346*
    (0.185)
    –0.050*
    (0.026)
    –0.225
    (0.197)
    –0.029
    (0.025)
    –0.171
    (0.193)
    –0.022
    (0.025)
    –0.171
    (0.193)
    –0.022
    (0.025)
    Preceding customer0.174**
    (0.073)
    0.025**
    (0.011)
    0.150*
    (0.077)
    0.019*
    (0.010)
    0.158**
    (0.077)
    0.020**
    (0.010)
    0.158**
    (0.077)
    0.020**
    (0.010)
    Female0.172***
    (0.066)
    0.025***
    (0.009)
    0.128*
    (0.069)
    0.016*
    (0.009)
    0.125*
    (0.070)
    0.016*
    (0.009)
    0.125*
    (0.070)
    0.016*
    (0.009)
    Constant–4.986***
    (0.406)
    –5.376***
    (0.458)
    –5.324***
    (0.447)
    –5.324***
    (0.447)
    Middle–0.389***
    (0.138)
    –0.050***
    (0.018)
    End–0.222
    (0.137)
    –0.029
    (0.018)
    Token*Middle–0.393***
    (0.128)
    –0.056***
    (0.018)
    –0.389***
    (0.138)
    –0.050***
    (0.018)
    Token*End–0.257**
    (0.128)
    –0.037**
    (0.018)
    –0.222
    (0.137)
    –0.029
    (0.018)
    Observer FEYesYesYesYes
    Cashier FEYesYesYesYes
    Week FENoYesNoNo
    Pseudo R–squared0.3300.3910.3890.390
    • Note:n = 5,513. Standard errors appear in parentheses. Model I uses the total number of items purchased, and model II splits the total number of items purchased into small, medium, and large items. Models III and IV repeat models I and II, respectively, except that models III and IV consider week fixed effects. Models III’ and IV’ repeat model III and IV, respectively, except that models III’ and IV’ consider groups of weeks instead of individual week fixed effects. Models III” and IV” repeat models III and IV, respectively, except that models III” and IV” consider interaction between token and groups of weeks instead of individual week fixed effects.

    • * p < 0.1

    • ** p < 0.05

    • *** p < 0.01