Fig 1.
Illustration of the experimental design.
This is a 2 (revenue source) x 3 (expenditure domain) between-participants design, with participants randomly allocated to one of six conditions. When carbon tax revenues are earmarked towards the environmental domain, it is a “matched earmarking” scheme. When carbon tax revenues are earmarked towards participants’ preferred policy domain, it is a “mismatched earmarking” scheme.
Fig 2.
Bar graphs representing policy support for a carbon tax increase when revenues are either earmarked for environmental protection (‘matched earmarking’) or not earmarked, for each study (N1A = 706, N1B = 429).
Policy support was rated on a ten-point Likert scale. Data points from the two British samples are combined. Plotted are 95% confidence intervals.
Fig 3.
Mean policy support when tax revenues, coming from a generic tax or a carbon tax increase, are either earmarked towards participants’ preferred policy domain, towards environmental protection or not earmarked (pooled into the general budget), in each study (N1A = 2096, N1B = 1271).
Policy support was rated on a ten-point Likert scale. Data points from the two British samples are combined. Plotted are 95% CIs.
Fig 4.
Mean policy support in the British study for the four earmarked tax schemes (revenue source: Generic tax or carbon tax; expenditure domain: Preferred policy domain or environmental domain), when splitting the sample according to the priority given to environmental protection, political trust, social trust, political ideology, highest education level, gender, age, perceived relative income level and residence area (see Note D in S1 Text for the detailed procedure).
Policy support was rated on a ten-point Likert scale. Data points from the two British samples are combined (Ntotal = 1250). Plotted are 95% CIs.
Fig 5.
Mean policy support for the four earmarked tax schemes in all of the British studies (carbon tax: Study 1A, inheritance tax: Study 2A, tobacco tax: Study 2A’).
Policy support was rated on a ten-point Likert scale. The matched earmarking domain corresponds to: (a) environmental protection in the carbon tax study, (b) poverty reduction programs in the inheritance tax study, (c) health and tobacco control programs in the tobacco tax study. Plotted are 95% CI.
Fig 6.
Mean policy support in the British study (N3A = 801) and in the French study (N3B = 758) when either 0%, 25%, 50%, 75% or 100% of carbon tax revenues are earmarked for environmental protection.
Policy support was rated on a ten-point Likert scale. Plotted are 95% CIs. Average levels of support when either 0% or 100% of carbon tax revenues are earmarked for environmental protection are consistent with those observed in Study 1.
Fig 7.
Average ranking scores (ranging between 1 and 3 where 1 is the most preferred scheme and 3 the least preferred scheme) when either 75% of carbon tax revenues are earmarked for environmental protection and 25% redistributed as a cash transfer to the three lowest income deciles, that can only be spent on pro-environmental expenses (“environmental cash transfer”), 75% of carbon tax revenues are earmarked for environmental protection and 25% redistributed as an unconditional cash transfer to the three population deciles with lowest income (“unconditional cash transfer”), or 100% of carbon tax revenues are earmarked for environmental protection (“no cash transfer”).
Results are plotted for each study (N4A = 649, N4B = 643).