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Field
Trial Start Date
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Before
April 07, 2022
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After
September 28, 2022
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Field
Trial End Date
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Before
July 31, 2022
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After
January 15, 2023
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Field
Last Published
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Before
May 26, 2022 11:46 AM
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After
November 16, 2022 03:26 PM
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Field
Intervention (Public)
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Before
1. Control: The benchmark treatment
2. Feedback group: Give users information about their historical parking behavior and the location of designated areas.
3. Comparison group: Use texts to inform users on how their orderly parking rate compares to similar users.
4. Individual incentive group: Users will receive free-riding tickets. The number of additional free days they receive is a function of the increase in their orderly parking rate.
5. Group incentive group: Users will be paired and receive free-riding tickets. The number of additional free days they receive is a function of the increase in their joint orderly parking rate.
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After
1. Control: The benchmark treatment
2. Comparison group: Use texts to inform users on how their orderly parking rate compares to similar users.
3. Individual incentive group: Users will receive free-riding tickets. The number of additional free days they receive is a function of the increase in their orderly parking rate.
4. Group incentive group: Users will be paired and receive free-riding tickets. The number of additional free days they receive is a function of the increase in their joint orderly parking rate.
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Field
Intervention Start Date
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Before
May 27, 2022
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After
November 17, 2022
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Field
Intervention End Date
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Before
June 27, 2022
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After
December 31, 2022
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Field
Experimental Design (Public)
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Before
During the treatment period, users in the treatments groups will receive feedback information on their individual past parking behavior, complemented with either a) social comparison information on the past parking behavior of other, similar users, b) an individual incentive in the form of free-riding cards, c) a group incentive in the form of free-riding cards.
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After
During the treatment period, users in the treatments groups will receive one following incentives randomly: a) social comparison information on the past parking behavior of other, similar users, b) an individual incentive in the form of free-riding cards, c) a group incentive in the form of free-riding cards.
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Field
Planned Number of Clusters
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Before
2 589 users. Explanation: In campus markets of bike-sharing, we randomly select 2 589 users with five more trips during one month from the Hellobike sample pool. These users will be assigned to the control (T1) and treatment groups (T2-T5).
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After
8136 users. Explanation: The researchers received summary data on the trips and parking behavior of 81,372 active shared-bicycle users in the period 28.09.2022 - 27.10.2022. This is the pre-experimental period (period A in Figure 1). From this initial sample, we classfied users as treatment-eligible when they user-pattern in the pre-experimental period satisfied the following conditions:
a) the user has completed at least 10 trips
b) the average trip-distance was not less than 200 meter and not more than 6000 meter.
c) the user's age was not more than 35 years.
These conditions were motivated by our objective to focus on active student-users on the campuses.
A total of 69,648 users satisfied all conditions. Of these 8,136 (10 per cent of the original sample) were randomly assigned to one of the four treatments. Exactly 2,034 users were assigned to each treatment. We applied a stratified design that balanced treatment groups on the pre-experimental average good parking rate, campus location, age, gender and average trip distance
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Field
Planned Number of Observations
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Before
Not sure
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After
8136 users.
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Field
Sample size (or number of clusters) by treatment arms
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Before
T1 Control: about 518 users
T2 Feedback group: about 517 users
T3 Comparison group: 518 users
T4 Individual incentive group: 518 users
T5 Group incentive group: 518 users
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After
T1 Control: about 2034 users
T2 Comparison group: 2034 users
T3 Individual incentive group: 2034 users
T4 Group incentive group: 2034 users
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Field
Power calculation: Minimum Detectable Effect Size for Main Outcomes
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Before
Unit of measurement: the fraction of trips ending in crowded areas at the individual user level. For a type I error probability of alpha = 0.05 and a power of 1- k = 0.8, and N =518 per treatment arm, the standardized minimum detectable effect size is 0.175 standard deviations. The standard deviation of out outcome variable is highest when half of the users always parks in a crowded area and the other half never, in which case s.d. = 0.5. In this most extreme case, the minimum detectable effect size (MDE) would be a change in parking in disorderly areas of about 8.8 percentage points (=0.5x0.175). If only half of the selected individuals takes up treatment (that is: completes at least one trip in the experimental period), the MDE would increase to 12.3 percentage points. Increasing the power to 1-k =0.9 increases the MDE to 10.1 percentage points.
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After
Unit of measurement: the fraction of trips ending in designated parking areas at the individual user level. For a type, I error probability of alpha = 0.05 and a power of 1- k = 0.8, and N =20 343 per treatment arm, the standardized minimum detectable effect size is 0.087 standard deviations. The standard deviation of outcome variable is highest when half of the users always park in a crowded area and the other half never, in which case s.d. = 0.5. In this most extreme case, the minimum detectable effect size (MDE) would be a change in parking in disorderly areas of about 4.4 percentage points (=0.5x0.087). If only half of the selected individuals take up treatment (that is: complete at least one trip in the experimental period), the MDE would increase to 6.2 percentage points. Increasing the power to 1-k =0.9 increases the MDE to 7.2 percentage points.
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Field
Intervention (Hidden)
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Before
T1 Control:
Users receive reminder messages (by app and SMS) which remind them of the appearance of designated parking areas.
T2 Feedback group:
Users receive messages (by app and SMS) which inform them on how often they parked their shared bicycles in designated areas in the past month (as percentage of their total number of trips) and which remind them of the appearance of designated parking areas.
T3 Comparison group:
Users receive messages (by app and SMS) which inform them on how often they parked their shared bicycles in designated areas in the past month (as percentage of their total number of trips) and which remind them of the appearance of designated parking areas. In addition, they will receive information on how their orderly parking rate compares to other, similar users.
T4 Individual incentive group:
Users receive messages (by app and SMS) which inform them on how often they parked their shared bicycles in designated areas in the past month (as percentage of their total number of trips) and which remind them of the appearance of designated parking areas. In addition, this treatment provides users an incentive in the form of a free-riding card which they receive conditional on their orderly parking behavior. A user receives a 1-day or 3-day free-riding card after each stage of the campaign has ended if his or her orderly parking rate is between 40% and 60% or exceeds 60%.
T5 Group incentive group:
Users receive messages (by app and SMS) which inform them on how often they parked their shared bicycles in designated areas in the past month (as percentage of their total number of trips) and which remind them of the appearance of designated parking areas.
In addition, this treatment pairs two random users as bikemates. Both users of a pair will receive a 1-day free-riding ticket if each of their orderly parking rates is between 40% and 60% during the campaign. They will each receive a 3-day free-riding card if the orderly parking rate of both users exceed 60%.
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After
T1 Control:
Users receive reminder messages (by app and SMS) which remind them of the appearance of designated parking areas.
T2 Comparison group:
Users receive messages (by app and SMS) which inform them on how often they parked their shared bicycles in designated areas in the past month (as percentage of their total number of trips) and which remind them of the appearance of designated parking areas. In addition, they will receive information on how their orderly parking rate compares to other, similar users.
T3 Individual incentive group:
Users receive messages (by app and SMS) which inform them on how often they parked their shared bicycles in designated areas in the past month (as percentage of their total number of trips) and which remind them of the appearance of designated parking areas. In addition, this treatment provides users an incentive in the form of a free-riding card which they receive conditional on their orderly parking behavior. A user receives a 1-day or 3-day free-riding card after each stage of the campaign has ended if his or her orderly parking rate is between 40% and 60% or exceeds 60%.
T4 Group incentive group:
Users receive messages (by app and SMS) which inform them on how often they parked their shared bicycles in designated areas in the past month (as percentage of their total number of trips) and which remind them of the appearance of designated parking areas.
In addition, this treatment pairs two random users as bikemates. Both users of a pair will receive a 1-day free-riding ticket if each of their orderly parking rates is between 40% and 60% during the campaign. They will each receive a 3-day free-riding card if the orderly parking rate of both users exceed 60%.
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