| Field | Before | After |
|---|---|---|
| Field Trial Start Date | Before March 20, 2026 | After April 01, 2026 |
| Field Trial End Date | Before April 27, 2026 | After April 30, 2026 |
| Field Last Published | Before March 12, 2026 04:47 AM | After April 16, 2026 12:05 PM |
| Field Intervention Start Date | Before March 20, 2026 | After April 01, 2026 |
| Field Intervention End Date | Before April 27, 2026 | After April 30, 2026 |
| Field Primary Outcomes (End Points) | Before The primary outcome is the number of units purchased in Round 1, Yi1 = {0,1,2,3}, treated as continuous. This measure also provides the participants desired level for the experimenters commitment to retire carbon emission allowances equivalent to 50 pounds of CO2. | After The primary outcome is the number of units purchased in Round 1, Yi1 = {0,1,2,3,4}, treated as continuous. This measure also provides the participants desired level for the experimenters commitment to retire carbon emission allowances equivalent to 50 pounds of CO2 per unit not purchased. |
| Field Experimental Design (Public) | Before The study uses a between-subjects experimental design with random assignment to one of five incentive conditions: no rebate, sure rebate, or a probabilistic rebate with a 50%, 25%, or 10% probability. Participants complete a sequence of four decision rounds. In each round, they choose how many units (0–3) of a fictitious consumption good to purchase at a fixed price. Each unit provides a privately induced monetary value to the participant, while consumption is associated with carbon emissions that can be offset by the researchers depending on participants' choices. In rebate conditions, participants are informed that they may receive a monetary rebate linked to the number of units they choose not to consume. The structure of the rebate varies by treatment in terms of the probability with which it is paid. Participants receive feedback after each round about their own choices and the corresponding carbon offset. At the end of the experiment, one round is randomly selected to determine monetary payoffs. Randomization is conducted at the individual level, and all participants face the same price, values, and decision environment aside from the rebate probability. The design allows comparison of choices across incentive conditions and across rounds within individuals. | After The study uses a between-subjects experimental design with random assignment to one of five incentive conditions: no rebate, sure rebate, or a probabilistic rebate with a 50%, 25%, or 10% probability. Participants complete a sequence of four decision rounds. In each round, they choose how many units (0–4) of a fictitious consumption good to purchase at a fixed price. Each unit provides a privately induced monetary value to the participant, while consumption is associated with carbon emissions that can be offset by the researchers depending on participants' choices. In rebate conditions, participants are informed that they may receive a monetary rebate linked to the number of units they choose not to consume. The structure of the rebate varies by treatment in terms of the probability with which it is paid. Participants receive feedback after each round about their own choices and the corresponding carbon offset. At the end of the experiment, one round is randomly selected to determine monetary payoffs. Randomization is conducted at the individual level, and all participants face the same price, values, and decision environment aside from the rebate probability. The design allows comparison of choices across incentive conditions and across rounds within individuals. |
| Field Planned Number of Observations | Before Planned Number of Observations: 1,012 individual participants * 4 rounds = 4,048. N = 1,012 is chosen to achieve 80% power at alpha=0.05 for the primary Sure vs 10% contrast with MDE=0.20 under the prespecified unequal allocation. | After Planned Number of Observations: 1,036 individual participants * 4 rounds = 4,144. N = 1,012 is chosen to achieve 80% power at alpha=0.05 for the primary Sure vs 10% contrast with MDE=0.20 under the prespecified unequal allocation. |
| Field Sample size (or number of clusters) by treatment arms | Before No rebate (control): 101 participants Sure rebate (100%): 355 participants 50% rebate: 101 participants 25% rebate: 100 participants 10% rebate: 355 participants Total: 1,012 participants | After No rebate (control): 104 participants Sure rebate (100%): 362 participants 50% rebate: 104 participants 25% rebate: 104 participants 10% rebate: 362 participants Total: 1,036 participants |
| Field Intervention (Hidden) | Before Participants complete an online, incentivized experiment in which they make four repeated consumption decisions under a fixed price that incorporates a carbon-related charge. In each round, participants choose an integer number of units 𝑛={0, 1, 2, 3} of a fictitious product. Each unit provides a declining private value: the first unit yields a value of $6, the second unit a value of $4, and the third unit a value of $2. The price per unit is fixed at $2.50 in all rounds and treatments. Monetary payoffs in each round are determined by the sum of the private values of the units purchased minus total expenditures. Consumption choices are linked to real environmental consequences. For each unit not consumed, the experimenters commit to retire carbon emission allowances equivalent to 50 pounds of CO2. Thus, if a participant foregoes all three units, 150 pounds of CO2 are retired; if two units are foregone, 100 pounds are retired; if one unit is foregone, 50 pounds are retired; and if all three units are purchased, no allowances are retired. These offsets are implemented by the research team upon completion of the study. Participants are randomly assigned to one of several treatment conditions that differ in the presence and structure of a cash rebate. In the no-rebate control condition, participants receive no rebate regardless of their consumption choices. In the sure rebate condition, participants receive a guaranteed rebate of $0.50 for each unit not consumed. In probabilistic rebate conditions, the per-unit rebate amount remains $0.50, but it is awarded only with a specified probability. Specifically, participants in the 50% treatment receive the rebate with 50% probability, participants in the 25% treatment receive it with 25% probability, and participants in the 10% treatment receive it with 10% probability. In probabilistic treatments, the rebate lottery is resolved independently at the end of the experiment for the payoff-relevant round. The decision task is repeated for four rounds. To preserve incentive compatibility while limiting total payments, one of the four rounds is randomly selected at the end of the experiment to determine the participant's final payoff. Participants receive feedback after each round about their monetary payoff and the associated carbon offset. All payments are made in real money. In addition to the main decision task, participants complete a short incentivized task to elicit individual risk preferences, as well as a demographic questionnaire. The experimental design allows for a comparison of consumption behavior under guaranteed versus probabilistic rebate schemes and for an assessment of how responses vary systematically with the probability of receiving a rebate, while holding prices and private values constant. | After Participants complete an online, incentivized experiment in which they make four repeated consumption decisions under a fixed price that incorporates a carbon-related charge. In each round, participants choose an integer number of units n={0, 1, 2, 3, 4} of a fictitious product. Each unit provides a declining private value: the first unit yields a value of $15, the second unit a value of $14.5, the third unit a value of $14 and the fourth unit a value of $13.5. The price per unit is fixed at $13 in all rounds and treatments. Monetary payoffs in each round are determined by the sum of the private values of the units purchased minus total expenditures. Consumption choices are linked to real environmental consequences. For each unit not consumed, the experimenters commit to retire carbon emission allowances equivalent to 50 pounds of CO2. Thus, if a participant foregoes all four units, 200 pounds of CO2 are retired; if three units are foregone, 150 pounds of CO2 are retired; if two units are foregone, 100 pounds are retired; if one unit is foregone, 50 pounds are retired; and if all four units are purchased, no allowances are retired. These offsets are implemented by the research team upon completion of the study. Participants are randomly assigned to one of several treatment conditions that differ in the presence and structure of a cash rebate. In the no-rebate control condition, participants receive no rebate regardless of their consumption choices. In the sure rebate condition, participants receive a guaranteed rebate of $2 for each unit not consumed. In probabilistic rebate conditions, the per-unit rebate amount remains $2, but it is awarded only with a specified probability. Specifically, participants in the 50% treatment receive the rebate with 50% probability, participants in the 25% treatment receive it with 25% probability, and participants in the 10% treatment receive it with 10% probability. In probabilistic treatments, the rebate lottery is resolved independently at the end of the experiment for the payoff-relevant round. The decision task is repeated for four rounds. To preserve incentive compatibility while limiting total payments, one of the four rounds is randomly selected at the end of the experiment to determine the participant's final payoff. Participants receive feedback after each round about their monetary payoff and the associated carbon offset. All payments are made in real money. In addition to the main decision task, participants complete a short incentivized task to elicit individual risk preferences, as well as a demographic questionnaire. The experimental design allows for a comparison of consumption behavior under guaranteed versus probabilistic rebate schemes and for an assessment of how responses vary systematically with the probability of receiving a rebate, while holding prices and private values constant. |
| Field | Before | After |
|---|---|---|
| Field Document | Before |
After
carbon_pricing_and_lottery_incentives.pdf
MD5:
e7e3af13075f8a0db1bd3db0ff5f03d0
SHA1:
4b9f211d0ddf66af6c08ece37c015d1cf294abdf
|
| Field Title | Before | After Sample size calculations |
| Field | Value |
|---|---|
| Field Document |
Value
carbon_pricing_and_lottery_incentives_power_analysis.pdf
MD5:
c3f431d5e44dc5b58d77c65d032dea36
SHA1:
12297bbe80a76bea14afdf3b97745694165156ba
|
| Field Title | Value Power analysis |