A field experiment on financial incentive, social preference, and peer effects to improve parking by bike-sharing users

Last registered on November 08, 2021

Pre-Trial

Trial Information

General Information

Title
A field experiment on financial incentive, social preference, and peer effects to improve parking by bike-sharing users
RCT ID
AEARCTR-0008504
Initial registration date
November 06, 2021
Last updated
November 08, 2021, 10:51 AM EST

Locations

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Primary Investigator

Affiliation
Beijing Jiaotong University

Other Primary Investigator(s)

PI Affiliation
Beijing Jiaotong University
PI Affiliation
University of Groningen

Additional Trial Information

Status
In development
Start date
2021-09-16
End date
2022-01-30
Secondary IDs
National Natural Science Foundation of China and the Joint Programming Initiative Urban Europe, National Natural Science Foundation of China
Prior work
This trial does not extend or rely on any prior RCTs.
Abstract
Dockless bike-sharing is popular and provides the commuting service for "the last mile of trip". Hellobike company also taps over 450 university markets, where some shared bicycles only serve students and exclusively circulate on university campuses. In this study, we design different treatments that vary in the extent to which they appeal to users’s considerations for other users, to test the role of social preferences in bike-sharing. In a field experiment, we design four treatments: social norms, individual free-ticket, group free-ticket, and feedbacks.
External Link(s)

Registration Citation

Citation
Wang, Yacan, Adriaan Soetevent and Duan Su. 2021. "A field experiment on financial incentive, social preference, and peer effects to improve parking by bike-sharing users." AEA RCT Registry. November 08. https://doi.org/10.1257/rct.8504-1.0
Sponsors & Partners

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Experimental Details

Interventions

Intervention(s)
Social norms: Use information to tell users what is orderly parking, why important, and how to make orderly parking.
Individual free-ticket: Users will get free tickets to ride for the increase of orderly parking rate.
Group free-ticket: Use free tickets to ride for the subject and her partner and monthly feedbacks to encourage orderly parking.
Feedbacks: Use free tickets to ride for the subject and monthly feedbacks to increase the orderly parking.
Intervention Start Date
2021-11-08
Intervention End Date
2021-12-31

Primary Outcomes

Primary Outcomes (end points)
Change in fraction of bicycles in each treatment group that is parked in crowded areas
Primary Outcomes (explanation)
Each user i will complete Ti trips (Ti =0,1,…) in the experimental period. Each trip t will end in a crowdeddesigned area (xit = 1) or not (xit = 0). Per individual with Ti >0 , we compute the average value (x_i ) ̅= 1/T_i ∑_(t=1)^(T_i)▒x_it The prime outcome variable is the fraction of trips that ends in crowded designed areas, averaged over all users in a treatment group.

Secondary Outcomes

Secondary Outcomes (end points)
The change of social norms and social preference before and after treatment.
Secondary Outcomes (explanation)
Subjects are exposed to the treatment of social norms and social preferences. During the treatment period, subjects will know the social norms of orderly parking and potentially experience altruism or reciprocity from others. It is conceivable that the treatment will influence subjects i’ social norms and social preferences.

Experimental Design

Experimental Design
During the treatment period, users will be incentivized by social norms, free riding, the interaction of free tickets and social preference, or the interaction of free tickets and feedbacks.
Experimental Design Details
Not available
Randomization Method
Stratified randomization with Stata
Randomization Unit
Individual user
Was the treatment clustered?
No

Experiment Characteristics

Sample size: planned number of clusters
5200 users. In four-campus markets of bike-sharing, we randomly select 6000 users from the Hellobike sample pool. After data cleaning, keep valid subjects 5222. These users will be assigned to the control and treatment groups T1-T5. For T4 and T5, we double the subject size.
Sample size: planned number of observations
5200 users
Sample size (or number of clusters) by treatment arms
T1 Control: about 746 users
T2 Social norms: 746 users
T3 Individual free-ticket: 746 users
T4 Group free-ticket: 1492 users
T5 Feedbacks: 1492 users
Minimum detectable effect size for main outcomes (accounting for sample design and clustering)
Unit of measurement: the fraction of trips ending in designed 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 =743 per treatment arm, the standardized minimum detectable effect size is 0.145 standard deviations. In the experimental area, the benchmark percentage of parking in designed areas is about 2%. We expect to increase the percentage from 2% to 3% more.
IRB

Institutional Review Boards (IRBs)

IRB Name
Information provision to reduce the parking of shared bicycles in crowded areas
IRB Approval Date
2021-07-15
IRB Approval Number
FEB-20210715-13124