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Field
Trial Start Date
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Before
March 07, 2024
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After
April 12, 2024
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Last Published
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Before
March 15, 2024 04:16 PM
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After
April 12, 2024 06:38 AM
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Intervention Start Date
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Before
March 07, 2024
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After
April 12, 2024
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Intervention End Date
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Before
March 29, 2024
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After
May 03, 2024
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Field
Experimental Design (Public)
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Before
The experiment consists of two parts: (i) a quality elicitation step (Task 1) and (ii) a choice task (Task 2). In the quality elicitation step, we elicit subjective quality values of 24 consumer products using a multiple price list (MPL) method. Specifically, it measures the quality value of a product by asking a subject whether they prefer the product (Option A) to an amount of money (Option B). We ask this binary question multiple times by varying the amount of money in Option B ranging from $0.01 to $8 in increments of 1 cent. We expect that a subject chooses Option A in some initial questions, switches to Option B at a certain question, and chooses Option B for the remaining questions. We say that the dollar value at the switch point is the subjective quality of a product.
Before the main choice task, we select two sets of two-paired products in which (i) the elicited quality values are greater than or equal to $0.05, (ii) the elicited quality values are smaller than or equal to $6, and (iii) the difference in elicited quality values in each product set is greater than or equal to $0.5.
In the main choice task, a subject chooses the most preferred alternative from a choice set consisting of three alternatives. Note that the first and the second alternatives are bundles of a product and money while the third alternative is simply a money option, i.e., (Product 1, Money 1), (Product 2, Money 2), (Money 3). Product 1 and Product 2 are from a selected product set before the main choice task as described above. Money 3 is an endowment, and in this experiment, it can be either $8 or $10. In this case, the third alternative can be interpreted as an outside option, which is simply taking an endowment. Money 1 and Money 2 are calculated at the subject level based on the elicited quality values and the endowment so that we can distinguish and test the pairwise normalization model and the range normalization model. Specifically, once a product set and an endowment are fixed, we generate four choice sets in which the pairwise normalization model and the range normalization model provide different predictions. Remember that we have two product sets (i.e., product set 1 and product set 2) and two endowments (i.e., $8 and $10). Hence, each subject makes decisions for 16 choice sets.
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After
The experiment is composed of two parts: (i) a quality elicitation step (Task 1) and (ii) a main choice task (Task 2).
In the quality elicitation task, we elicit subjective quality values of 24 consumer products using a multiple price list method. Consumer products used in the experiment are snacks that are familiar to student subjects. In each round, a picture, a name, and a weight of a product appear on a screen. Then a subject is asked whether they prefer the product (Option A) to an amount of money (Option B). This binary question is asked multiple times by varying the amount of money in Option B ranging from $0.01 to $8 in increments of $0.01. Instead of asking a subject to make 800 choices in each round, we ask them at which dollar value they would like to switch from Option A to Option B. Once they report the switch point, then Option A is chosen for the first question to the question right before the switch point, and Option B is chosen for all questions after the switch point. We say that a dollar value at the switch point is a subjective quality value of a product. The order of rounds is randomized at the subject level.
Before the main choice task, we select four sets of two-paired products in which (i) the elicited quality values are greater than or equal to $0.10, (ii) the elicited quality values are smaller than or equal to $6, and (iii) the difference in elicited quality values in each product set is greater than or equal to $0.5.
In the main choice task, a subject chooses the most preferred alternative from a choice set consisting of three alternatives. Note that the first and the second alternatives are bundles of a product and money while the third alternative is simply a money option, i.e., (Product 1, Money 1), (Product 2, Money 2), (Money 3). Product 1 and Product 2 are from a selected product set before the main choice task as described above. Money 3 is an endowment, and in this experiment, it can be either $8 or $10. In this case, the third alternative can be interpreted as an outside option, which is simply taking an endowment. Money 1 and Money 2 are calculated at the subject level based on the elicited quality values and the endowment so that we can distinguish and test the pairwise normalization model and the range normalization model. Specifically, once a product set and an endowment are fixed, we generate six choice sets in which the pairwise normalization model and the range normalization model provide different predictions. Remember that we have four product pair sets and two endowments. Hence, each subject makes 48 choices.
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Field
Randomization Unit
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Before
Each subject faces 24 rounds in Task 1 and 16 rounds in Task 2. Remember that a subject makes a switch point decision in each round in Task 1, and a subject chooses the most preferred alternative in each round in Task 2. Each subject always starts with Task 1 and then Task 2. The order of rounds in Task 1 is randomized. In Task 2, the order of rounds is randomized, and the order of alternatives in each round is randomized as well. In the payment stage, one round in Task 1 and Task 2 is randomly chosen. If Task 1 is randomly selected, then one binary question is randomly selected to determine the payment.
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After
Each subject faces 24 rounds in Task 1 and 48 rounds in Task 2. Remember that a subject makes a switch point decision in each round in Task 1, and a subject chooses the most preferred alternative in each round in Task 2. Each subject always starts with Task 1 and then Task 2. The order of rounds in Task 1 is randomized. In Task 2, the order of rounds is randomized, and the order of alternatives displayed on a computer screen in each round is randomized as well. In the payment stage, one round in Task 1 and Task 2 is randomly chosen. If Task 1 is randomly selected, then one binary question is randomly selected to determine the payment.
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Field
Planned Number of Clusters
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Before
Based on a pre-analysis including power analysis by simulation, the target number of subjects is 80 students. However, we may have to exclude some observations if elicited quality values do not satisfy the criteria of choosing product sets as described above. To collect 80 subjects who pass the criteria, the actual number of collected subjects can be more than 80.
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After
Based on a pre-analysis including a power analysis by simulation, the target number of subjects is 60 students.
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Field
Planned Number of Observations
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Before
The main variable of interest is choices in the main choice task. If we have 80 subjects, then we have 1,280 choices since each subject makes 16 choices in the main choice task (80x16=1,280).
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After
The main variable of interest is 48 choices in the main choice task. If we have 60 subjects, then the total number of choices is 2,880.
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Field
Sample size (or number of clusters) by treatment arms
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Before
Based on a pre-analysis including power analysis by simulation, the target number of subjects is 80 students. However, we may have to exclude some observations if elicited quality values do not satisfy the criteria of choosing product sets as described above. To collect 80 subjects who pass the criteria, the actual number of collected subjects can be more than 80.
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After
Based on a pre-analysis including a power analysis by simulation, the target number of subjects is 60 students.
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